Method and apparatus for determining resource pool

ABSTRACT

A method includes receiving, at a mobile device, resource pool configuration information, the resource pool configuration information comprising a bitmap to determine the resource pool and determining, for a period having a plurality of consecutive subframes, a first subset of subframes by excluding, from the plurality of consecutive subframes, subframes in which a sidelink synchronization signal (SLSS) resource is configured and subframes other than uplink subframes. The method also includes determining, for the period, a second subset of subframes by excluding, from the first subset of subframes, one or more subframes, wherein a quantity of the second subset of subframes corresponds to an integer multiple of a length of the bitmap, and determining, based on a plurality of repetitions of the bitmap, the resource pool for a sidelink transmission from the second subset of subframes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of Korean PatentApplication Nos. 10-2016-0126853, filed on Sep. 30, 2016, and10-2016-0137463, filed on Oct. 21, 2016, which are hereby incorporatedby reference in their entirety.

BACKGROUND 1. Field

The present disclosure relates to a wireless communication system, andmore particularly, to a method and apparatus for determining a resourcepool for vehicle-to-X (V2X) communication.

2. Discussion of the Background

The term Vehicle-to-X (V2X: vehicle-to-everything) communication refersto a communication scheme that exchanges or shares information (e.g.,traffic conditions or the like) through communication with roadwayinfrastructures and other vehicles during driving.

Control information, such as scheduling assignment (SA), needs to betransmitted from a transmission user equipment (Tx UE) to a reception UE(Rx UE) for V2X communication, and data may be transmitted/receivedbased on the control information. A set of resource candidates to beused for the transmission of control information and data for V2X may bedefined; this set is referred to as a resource pool. The resource poolfor V2X communication may be defined in the time domain and in thefrequency domain. The time-domain resource pool for V2X communicationmay be defined in units of subframes. However, there is an ever-presentneed for a detailed scheme for determining the time-domain resource poolfor V2X communication.

SUMMARY

The present disclosure provides a method and apparatus for determining aresource pool for V2X communication.

The present disclosure provides a method and apparatus for determining asubframe pool for V2X communication.

The present disclosure provides a method and apparatus for determining asubframe pool for V2X communication using a bitmap which is repeatedinteger-multiple times within a predetermined period.

A method may include receiving, at a mobile device, resource poolconfiguration information, the resource pool configuration informationcomprising a bitmap to determine the resource pool and determining, fora period having a plurality of consecutive subframes, a first subset ofsubframes by excluding, from the plurality of consecutive subframes,subframes in which a sidelink synchronization signal (SLSS) resource isconfigured and subframes other than uplink subframes. The method alsoincludes determining, for the period, a second subset of subframes byexcluding, from the first subset of subframes, one or more subframes,wherein a quantity of the second subset of subframes corresponds to aninteger multiple of a length of the bitmap, and determining, based on aplurality of repetitions of the bitmap, the resource pool for a sidelinktransmission from the second subset of subframes.

According to the present disclosure, there is provided a method andapparatus for determining a subframe pool for V2X communication suchthat control information and data are efficiently transmitted, whileavoiding collision with other transmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 1C, 2A, 2B, 2C, 3A, and 3B are diagrams illustrating a V2Xscenario.

FIGS. 4 and 5 are diagrams illustrating an example of a resource poolfrom the perspective of the time domain.

FIG. 6 is a diagram illustrating an example of a resource pool from theperspective of the frequency domain.

FIG. 7 is a diagram illustrating a process for determining an SA andData transmission subframe in a UE autonomous resource selection mode.

FIG. 8 is a diagram illustrating DCI and SCI in an eNodeB resourcescheduling mode.

FIG. 9 is a diagram illustrating SCI in the UE autonomous resourceselection mode.

FIG. 10 is a diagram illustrating the configuration of a subframe poolwithin a predetermined period.

FIG. 11 is a flowchart illustrating a method for determining a resourcepool.

FIG. 12 is a flowchart illustrating a method for determining a resourcepool.

FIG. 13 is a diagram illustrating the configuration of a wirelessdevice.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Exemplary embodiments of the present invention will be described morefully hereinafter with reference to the accompanying drawings, in whichexemplary embodiments of the invention are shown. Throughout thedrawings and the detailed description, unless otherwise noted, the samedrawing reference numerals are understood to refer to the same elements,features, and structures. In describing the exemplary embodiments,detailed description of known configurations or functions may be omittedfor clarity and conciseness.

The description herein is related to a wireless communication network.An operation completed in a wireless communication network may beperformed through a process of controlling a network and transmittingdata through a system that controls the wireless communication network(e.g., a base station [BS]), or may be performed in a user equipment(UE) connected to the wireless communication network.

That is, it is apparent that various operations may be performed forcommunicating with a terminal in a network composed of a plurality ofnetwork nodes including a base station (B S); these operations areexecutable by the BS or by other network nodes excluding the BS. ‘Basestation’ may be replaced with terms such as a fixed station, a Node B,an evolved Node B (eNB), an access point (AP), and the like. Also,‘terminal’ may be replaced with terms such as a User Equipment (UE), aMobile Station (MS), a Mobile Subscriber Station (MSS), a SubscriberStation (SS), a non-AP station (non-AP STA), and the like.

While the present invention has been shown and described in connectionwith the embodiments, it will be apparent to those skilled in the artthat modifications and variations can be made without departing from thespirit and scope of the invention as defined by the appended claims.Thus, the present invention is not limited to the embodiments herein andmay include all embodiments within the scope of the appended claims. Forexample, various exemplary embodiments will be described with respect to3GPP LTE or LTE-A systems; however, aspects of the illustratedembodiments may be applied to other mobile communication systems.

Terminologies and abbreviations used in the present disclosure aredefined as provided below.

D2D: Device to Device (communication)

ProSe: (Device to Device) Proximity Services

SL: Sidelink

SCI: Sidelink Control Information

PSSCH: Physical Sidelink Shared Channel

PSBCH: Physical Sidelink Broadcast Channel

PSCCH: Physical Sidelink Control Channel

PSDCH: Physical Sidelink Discovery Channel

SLSS: Sidelink Synchronization Signal (=D2DSS (D2D SynchronizationSignal))

SA: Scheduling Assignment

TB: Transport Block

TTI: Transmission Time Interval

RB: Resource Block

In V2X communication, control information transmitted from a userequipment (UE) to another UE may be referred to as scheduling assignment(SA). When a sidelink (SL) is used as a communication link between UEs,the control information may be referred to as sidelink controlinformation (SCI); in this case, the control information may betransmitted through a PSCCH.

In V2X communication, data that a UE transmits to another UE may beconfigured in units of TBs; in this case, the data may be transmittedthrough a PSSCH.

The present disclosure also defines an operation mode according to aresource assignment scheme for transmitting control information and datafor V2X communication or for direct link (e.g., D2D, ProSe, or SL)communication.

An eNodeB resource scheduling mode is a mode in which an eNodeB or arelay node schedules resources that a UE uses for transmitting V2X (ordirect link) control information and/or data, and the UE transmits theV2X (or direct link) control information and/or data through thescheduled resources. For example, the eNodeB or relay node providesscheduling information associated with resources for V2X (or directlink) transmission control information and/or data to a V2X (or directlink) Tx UE through Downlink Control Information (DCI). Accordingly, theV2X (or direct link) Tx UE transmits the V2X (or direct link) controlinformation and data to a V2X (or direct link) Rx UE; the V2X (or directlink) Rx UE may then receive V2X (or direct link) data based on the V2X(or direct link) control information.

A UE autonomous resource selection mode is a mode in which a UEautonomously selects resources to be used for transmitting controlinformation and data, then transmits the control information and data.Here, the resource is selected from a resource pool (i.e., a set ofresource candidates) through sensing or the like. For example, the V2X(or direct link) Tx UE transmits the V2X (or direct link) controlinformation and data to a V2X (or direct link) Rx UE, and the V2X (ordirect link) Rx UE may receive V2X (or direct link) data based on theV2X (or direct link) control information.

For the following examples, the eNodeB resource scheduling mode may bereferred to as mode 1 in direct link communication, and may be referredto as mode 3 in V2X communication. The UE autonomous resource selectionmode may be referred to as mode 2 in direct link communication, and maybe referred to as mode 4 in V2X communication.

Hereinafter, although embodiments of the present disclosure aredescribed from the perspective of V2X communication, the scope of thepresent disclosure is not limited to V2X communication. Rather, theembodiments may also be applied to direct link-based communication, suchas D2D, ProSe, SL communication, or the like.

V2X is a term that generally indicates V2V, V2P, and V2I/N. When used inassociation with LTE communication, V2V, V2P, and V2I/N may be definedas shown in Table 1.

TABLE 1 V2V covering LTE-based communication between vehicles V2Pcovering LTE-based communication between a vehicle and a device carriedby an individual (e.g., handheld terminal carried by a pedestrian,cyclist, driver or passenger) V2I/N covering LTE-based communicationbetween a vehicle and a roadside unit/networkA roadside unit (RSU) is a stationary infrastructure entity supportingV2X applications that can exchange messages with other entitiessupporting V2X applications.Note: RSU is a term frequently used in existing ITS specifications, andthe reason for introducing the term in 3GPP specifications is to makethe documents easier to read for the ITS industry. RSU is a logicalentity that combines V2X application logic with the functionality of aneNB (referred to as eNB-type RSU) or a UE (referred to as UE-type RSU).

V2X communication may include communication based on PC5, which is a D2Dcommunication link (i.e., a direct interface between two devicessupporting ProSe). For V2X operation, various scenarios described inTable 2, Table 3, and Table 4 are taken into consideration withreference to FIGS. 1A, 1B, 1C, 2A, 2B, 2C, 3A, and 3B. Hereinafter,FIGS. 1A-C may be collectively referred to as FIG. 1. FIGS. 2A-C may becollectively referred to as FIG. 2. FIGS. 3A and 3B may be collectivelyreferred to as FIG. 3.

FIGS. 1, 2, and 3 are diagrams illustrating a V2X scenario.

Table 2 and FIG. 1 illustrate a scenario that supports a V2X operationbased only on a PC5 interface (i.e., an SL interface or D2D interface).FIG. 1A illustrates a V2V operation. FIG. 1B illustrates a V2Ioperation. FIG. 1C illustrates a V2P operation.

TABLE 2 This scenario supports V2X operation based only on PC5. In thisscenario, a UE transmits a V2X message to multiple UEs in a local areausing a sidelink. For V2I, either the transmitter UE or the receiverUE(s) is a UE-type RSU. For V2P, either the transmitter UE or thereceiver UE(s) is a pedestrian UE.

Table 3 and FIG. 2 illustrate a scenario that supports a V2X operationbased only on a Uu interface (i.e., an interface between a UE and aneNodeB). FIG. 2A illustrates a V2V operation. FIG. 2B illustrates a V2Ioperation. FIG. 2C illustrates a V2P operation.

TABLE 3 This scenario supports V2X operation based only on Uu. In thisscenario, For V2V and V2P, a UE transmits a V2X message to E-UTRAN inthe uplink and E-UTRAN transmits it to multiple UEs in a local area inthe downlink. For V2I, when the receiver is an eNB-type RSU, a UEtransmits a V2I message to E-UTRAN (eNB-type RSU) in the uplink; whenthe transmitter is an eNB-type RSU, E-UTRAN (eNB-type RSU) transmits anI2V message to multiple UEs in a local area in the downlink. For V2P,either the transmitter UE or the receiver UE(s) is a pedestrian UE. Tosupport this scenario, E-UTRAN performs the uplink reception anddownlink transmission of V2X messages. For a downlink, E-UTRAN may use abroadcast mechanism.

Table 4 and FIG. 3 illustrate a scenario that supports a V2X operationthat uses both a Uu interface and a PC5 interface (i.e., an SL interfaceor a D2D interface). FIG. 3A illustrates scenario 3A from Table 4 andFIG. 3B illustrates scenario 3B from Table 4.

TABLE 4 This scenario supports V2V operation using both Uu and PC5.Scenario 3A In this scenario, a UE transmits a V2X message to other UEsin a sidelink. One of the receiving UEs is a UE-type RSU which receivesthe V2X message in a sidelink and transmits it to E-UTRAN in an uplink.E-UTRAN receives the V2X message from the UE-type RSU and then transmitsit to multiple UEs in a local area in a downlink. To support thisscenario, E-UTRAN performs uplink reception and downlink transmission ofV2X messages. For the downlink, E-UTRAN may use a broadcast mechanism.Scenario 3B In this scenario, a UE transmits a V2X message to E- UTRANin an uplink and E-UTRAN transmits it to one or more UE-type RSUs. Then,the UE-type RSU transmits the V2X message to other UEs in a sidelink. Tosupport this scenario, E-UTRAN performs uplink reception and downlinktransmission of V2X messages. For the downlink, E-UTRAN may use abroadcast mechanism.

Referring to FIGS. 4 through 6, descriptions will be provided inassociation with the configuration of a Scheduling Assignment (SA) poolfor a control channel (PSCCH) in which SA is transmitted, and inassociation with the configuration of a data pool for a data channel(PSSCH) in which data associated with SA is transmitted in V2X.

Here, the SA pool may be a set of resource candidates that are availablefor SA transmission; the data pool may be a set of resource candidatesthat are available for data transmission. That is, the SA pool is aresource pool for SA, and the data pool is a resource pool for data.Each resource pool may be referred to as a subframe pool from theperspective of the time domain, and may be referred to as a resourceblock pool from the perspective of the frequency domain.

The SA pool and the data pool which will be described in FIGS. 4 through6 may be defined in the UE autonomous resource selection mode (mode 4).

In the eNodeB resource scheduling mode (mode 3), resources correspondingto all sidelink subframes in the time domain (i.e., all uplink subframesin LTE) and resources corresponding to all resource blocks in a V2Xcarrier (i.e., a band, or a component carrier or a cell in the case ofcarrier aggregation) in the frequency domain may become a set ofresource candidates available for SA and/or data transmission.Alternatively, in the eNodeB resource scheduling mode (mode 3), an SApool and a data pool may be separately defined; the sets of resourcecandidates available for the SA and/or data transmission may thus beconfigured in the same manner as in the UE autonomous resource selectionmode (mode 4).

That is, the SA pool and the data pool which will be described withreference to FIGS. 4 through 6 may be defined in the UE autonomousresource selection mode (mode 4) and/or the eNodeB resource schedulingmode (mode 3).

Also, in the examples of FIGS. 4 through 6, a D2D Frame Number (DFN)period is merely an example for illustrative purposes. A period maycorrespond to a set of subframes, having the same number of subframes asthe number of subframes in a System Frame Number (SFN) period and havinga starting point which is the same as or different from the SFN period.For example, a single SFN period or a single DFN period may eachcorrespond to 10240 subframes, which in turn correspond to 10240 ms.

FIGS. 4 and 5 are diagrams illustrating an example of a resource poolfrom the perspective of the time domain.

With respect to an SA pool and a data pool, a subframe resource poolconfigured in the time domain is as shown in FIG. 4. As illustrated inFIG. 4, the subframes for the SA pool and the data pool for V2X may bedefined by a bitmap (e.g., 1100111011 in FIG. 4) which is repeated forall subframes excluding predetermined subframes. For example, the valueof 1 in the bitmap indicates a subframe for the SA pool and the datapool, and the value of 0 in the bitmap indicates a subframe which doesnot belong to the SA pool and the data pool. The subframes for the SApool and the data pool for V2X may be allowed to perform transmissionand/or reception of SA and/or data for a resource pool in V2X.

Here, “all subframes excluding predetermined subframes” may indicate theset of subframes remaining after excluding predetermined subframes fromall subframes belonging to a SFN or a DFN period, wherein thepredetermined subframes are, for example, subframes in which V2X ordirect link transmission in not allowed, or subframes used for otherpurposes beyond control information and/or data transmission in V2X (orin direct link transmission). For example, the predetermined subframesmay correspond to subframes used for the transmission of a SidelinkSynchronization Signal (SLSS), and/or may correspond to DL subframes orspecial subframes in Time Division Duplex (TDD), but the predeterminedsubframes are not limited to these types of subframe correspondences.However, an uplink (UL) subframe may be used as a sidelink (SL) subframein TDD.

Also, the repeatedly applied bitmap may be indicated by higher layersignaling such as Radio Resource Control (RRC) or the like. The lengthmay be 16, 20, or 100, but is not limited thereto. The subframeindication of resource pool information illustrated in FIG. 4 may be anexample of a field included in the higher layer signaling.

FIG. 4 illustrates an example assuming that the subframes for the SApool and the data pool in a V2X transmission share the same subframesand assuming that the “subframe indication or resource pool” signalingfield of FIG. 4 is configured for both the SA pool and the data pool bytaking into consideration that SA and data are transmitted in the samesubframe in V2X.

When V2X allows SA and data to be transmitted in different subframes,the subframes for the SA pool and the data pool for V2X may be differentfrom each other. This does not mean that SA and data are alwaystransmitted in different subframes, but rather that SA and data may betransmitted in the same subframe or may be transmitted in differentsubframes. To this end, the “subframe indication of resource pool”signaling field shown in FIG. 4 may be configured for the SA pool andthe data pool respectively, as shown in FIG. 5.

FIG. 6 is a diagram illustrating an example of a resource pool from theperspective of the frequency domain.

The example of FIG. 6 will describe a resource pool from the perspectiveof the frequency domain when SA and data are transmitted in the samesubframe.

With respect to an SA pool and a data pool, a subframe resource poolconfigured in the frequency domain is as shown in FIG. 6. As illustratedin FIG. 6, the configuration may be different based on whether a PSCCHtransmitted in the SA pool and a PSSCH transmitted in the data pool areor are not adjacent in the frequency domain (Adjacent betweenPSCCH/PSSCH state or Non-adjacent between PSCCH/PSSCH state). In thisinstance, whether or not a PSCCH and a PSSCH are adjacent may beindicated by higher layer signaling such as RRC or the like, using asignaling field that indicates whether PSCCH and PSSCH RBs are adjacentto each other.

The cases in which a PSCCH transmitted in the SA pool and a PSSCHtransmitted in the data pool are adjacent in the frequency domain may bedescribed as follows.

As illustrated in FIG. 4, in a subframe of a resource pool configured inthe time domain for V2X, a “Starting RB of sub-channels” signaling fieldcorresponding to the starting RB of sub-channels may be defined based ona single RB unit (or granularity) with respect to all RBs in thefrequency domain (from RB#0 to RB#(N^(UL) _(RB-)1)). Here, N^(UL) _(RB)denotes the total number of RBs corresponding to a system bandwidth. V2Xfor a sidelink is defined in a UL band, and thus SL can be substitutedfor UL. The “Starting RB of sub-channels” signaling field may beindicated by higher layer signaling, such as an RRC or the like. From anRB indicated by “Starting RB of sub-channels”, consecutive RBscorresponding to a total of K sub-channels belong to the data pool. Inthis instance, the number of RBs included in a single sub-channel may beindicated by a “Sub-channel size” signaling field indicating the size ofa sub-channel. The number of sub-channels, K, may be indicated by a“Number of sub-channels” signaling field, and may be included in higherlayer signaling (e.g., an RRC or the like).

Here, RBs with the lowest RB index in each sub-channel may belong to theSA pool and to the data pool, and one or more of them may be used forPSCCH transmission. For example, SA may be transmitted in an RB with thelowest index among the RBs that belong to the data pool.

The cases in which a PSCCH transmitted in the SA pool and a PSSCHtransmitted in the data pool are not adjacent in the frequency domainmay be described as follows.

As illustrated in FIG. 4, in a subframe of a resource pool configured inthe time domain for V2X, a “Starting RB of sub-channels” correspondingto the starting RB of sub-channels may be defined based on a single RBunit (or granularity) with respect to all RBs in the frequency domain(from RB#0 to RB#(N^(UL) _(RB)-1)). Here, N^(UL) _(RB) denotes the totalnumber of RBs corresponding to a system bandwidth. V2X for a sidelink isdefined in a UL band; thus UL can be replaced with SL. The “Starting RBof sub-channels” signaling field may be indicated by higher layersignaling, such as an RRC or the like. Consecutive RBs corresponding toa total of K sub-channels starting from an RB indicated as a “StartingRB of sub-channels” may belong to the data pool. In this instance, thenumber of RBs included in a single sub-channel may be indicated by a“Sub-channel size” signaling field indicating the size of a sub-channel.The number of sub-channels, K, may be indicated by a “Number ofsub-channels” signaling field, and may be included in higher layersignaling, such as an RRC or the like.

As illustrated in FIG. 4, in a subframe of a resource pool configured inthe time domain for V2X, a “Starting RB of PSCCH pool” corresponding toa starting RB of the SA pool may be defined based on a single RB unit(or granularity) with respect to all RBs in the frequency domain (fromRB#0 to RB#(N^(UL) _(RB)-1)). Here, N^(UL) _(RB) denotes the totalnumber of RBs corresponding to a system bandwidth. V2X for a sidelink isdefined in a UL band, and thus UL can be replaced with SL. The “StartingRB of PSCCH pool” signaling field may be indicated by higher layersignaling, such as an RRC or the like. A total of K consecutive RBsstarting from an RB indicates as a “Starting RB of PSCCH pool” maybelong to the SA pool. Here, K is the same value as the number ofsub-channels, K, in the data pool.

In the present disclosure, a subframe where SA is transmitted may bedetermined as follows.

A subframe in which SA is transmitted in the eNodeB resource schedulingmode (mode 3) is the first subframe included in a set of resourcecandidates. This subframe may be used for V2X on a V2X carrier or bandfrom among subframes existing 4 ms (or 4 subframes) away from a subframein which an eNodeB transmits downlink control information (DCI). When SAand data are transmitted in the same subframe, the subframe in which theSA is transmitted may be a subframe in which data is transmitted.

In the UE autonomous resource selection mode (mode 4), a UE may usesensing to autonomously determine a subframe in which SA is to betransmitted within the SA pool. When SA and data are transmitted in thesame subframe, the subframe in which the SA is transmitted may be asubframe where data is transmitted.

FIG. 7 is a diagram illustrating an example of determining an SA anddata transmission subframe in the UE autonomous resource selection mode(mode 4).

FIG. 7 illustrates an example of selecting a subframe, through sensing,for the transmission of a control channel and a data channel, from an SApool for a control channel (PSCCH) and a data pool for a data channelassociated with the SA pool.

A UE may select a resource for control channel and data channeltransmission by inferring a time resource that has a low probability ofbeing occupied by another UE. The UE achieves this by considering theresult of sensing during a predetermined period of time prior to thepoint in time (“TTI m” of FIG. 7) when data to be transmitted occurswhile sensing is performed in the SA pool and/or data pool. As anexample, the point in time may indicate the point in time when dataarrives from a higher layer to a lower layer (e.g., PHY layer). In thisinstance, the data is provided based on a MAC PDU unit from theperspective of the higher layer, and is provided based on a TB unit fromthe perspective of the lower layer. That is, “TTI m” indicates the pointin time that is used as a reference point for when a UEselects/reselects a resource.

As another example, the UE may recognize a resource that is occupied byanother UE through sensing performed in a sensing window whichcorresponds to an interval from “TTI m-a” to “TTI m-b”. The UE mayperform the transmission of a control channel and a data channel in aresource selected from among the resources remaining after excluding theresource that is occupied and used by the other UE from the resources inthe resource pool.

Here, the values of a and b may be set (e.g., a=b+1000, b=1) to providean interval corresponding to a DFN period prior to TTI m to be a sensingwindow, but this is merely an example and the values are not limitedthereto.

Subsequently, “TTI m+c” may correspond to a TTI in which SA#1 (the firstSA) is transmitted (the subframe in which SA#1 is transmitted when asingle TTI corresponds to a single subframe). “TTI m+d” may correspondto a TTI in which initial transmission of TB#1 (the first TB), which isindicated by SA#1 and is transmitted, is performed (e.g., a subframe inwhich the initial transmission of TB#1 is performed when a single TTIcorresponds to a single subframe). “TTI m+e” may correspond to a TTI inwhich retransmission of TB#1, which is indicated by SA#1 and istransmitted, is performed (e.g., a subframe in which retransmission ofTB#1 is performed when a single TTI corresponds to a single subframe).

FIG. 7 illustrates the example of taking into consideration that SA anddata are also transmitted in the same subframe, and thus, c=d.

“TTI m+c” may correspond to a TTI in which SA#2 (the second SA) istransmitted (a subframe in which SA#2 is transmitted when a single TTIcorresponds to a single subframe). “TTI m+d” may correspond to a TTI inwhich initial transmission of TB#2 (the second TB), which is indicatedby SA#2 and is transmitted, is performed (or a subframe in which initialtransmission of TB#2 is performed when a single TTI corresponds to asingle subframe). “TTI m+e” may correspond to a TTI in whichretransmission of TB#2, which is indicated by SA#2 and is transmitted,is performed (or a subframe in which retransmission of TB#2 is performedwhen a single TTI corresponds to a single subframe).

FIG. 7 illustrates the example of taking into consideration that SA anddata may be transmitted also in the same subframe, and thus, c′=d′.

Further, a point in time after P_(rsvp)*j elapses from the initialtransmission of TB#1 may be reserved for the initial transmission ofTB#2. In this instance, d′=d+P_(rsvp)*j For example, P_(rsvp) may equal100 and j may be signaled as a value from among values selected throughcarrier-specific (or band-specific) network configuration or throuth V2Xpre-configuration within the range of {0, 1, . . . , 10}. For example,the value of j may be indicated by being selected through a “Resourcereservation” signaling field of SCI included in SA. In this instance,when j=0, this indicates that the value of d′ does not exist. Thatis,thismeans that a resource for TB#2 transmission is not reserved aftera TTI correspondingelapses “P_(rsvp)*j” from “TTI m+d”.

Although the example of FIG. 7 has been described with the assumption ofthe UE autonomous resource selection mode (mode 4), the descriptionassociated with the relationship of TTIs subsequent to “TTI m”,excluding a sensing window, may also be applicable to the case of theeNodeB resource scheduling mode (mode 3). That is, excluding the sensingwindow in the example of FIG. 7, “TTI m+c” may correspond to the firstsubframe included in a set of resource candidates that may be used forV2X in a V2X carrier or band, selected from among subframes existing 4ms (4 subframes) away from a subframe in which an eNodeB transmitsdownlink control information.

FIG. 8 is a diagram illustrating DCI and SCI in the eNodeB resourcescheduling mode.

A subframe in which SA is transmitted in the eNodeB resource schedulingmode (mode 3) is the first subframe included in a set of the resourcecandidates which may be used for V2X on a V2X carrier or band, selectedfrom among subframes existing 4 ms (4 subframes) away from a subframe inwhich an eNodeB transmits downlink control information (DCI).

In this instance, the information required when a V2X (or direct link)Tx UE (UE A of FIG. 8) transmits SA and data to a V2X (or direct link)Rx UE (UE B of FIG. 8) may be indicated by an eNodeB to the UE A throughDCI. For example, the DCI may include information as listed in Table 5.

TABLE 5 DCI for V2X CIF: 3 bits Lowest index of sub-channel allocation:ceil(log2(K)): 0 to 5 bits SA contents Time gap between transmission andretransmission: 4 bits Frequency resource of initial and lasttransmission : ceil(log2(K*(K + 1)/2) = 0 to 8 bits

The information associated with a resource block, which is a resource inthe frequency domain used when UE A transmits SA to UE B in the subframein which the SA is transmitted, may be indicated by “CIF” correspondingto a carrier indication field in Table 5 and a “Lowest index ofsub-channel allocation” signaling field corresponding to the lowestindex of sub-channel allocation.

The DCI in the eNodeB resource scheduling mode (mode 3) may includecontent related to Sidelink Control Information (SCI) as controlinformation (Scheduling Assignment (SA)) associated with datatransmission from UE A to UE B. In this instance, the content related tothe SCI, which is indicated by being included in the DCI, may include a“Time gap between transmission and retransmission” value correspondingto the time gap between transmission and retransmission, and a“Frequency resource of initial and last transmission” signaling fieldindicating the frequency resource of a last transmission, as shown inTable 5.

Also, in various embodiments of the present disclosure, values called“Time gap between transmission and retransmission” and/or “Frequencyresource of initial and last transmission” are merely examples, and thenames do not limit the scope of the present invention. For example, theinformation indicated by “Time gap between transmission andretransmission” and/or “Frequency resource of initial and lasttransmission” may be changed based on a predetermined condition. In thepresent disclosure, the “Time gap between transmission andretransmission” field may be referred to as the first field, and the“Frequency resource of initial and last transmission” field may bereferred to as the second field.

FIG. 9 is a diagram illustrating SCI in the UE autonomous resourceselection mode.

In the UE autonomous resource selection mode (mode 4), a UE mayautonomously determine the subframe in which SA is to be transmittedfrom a SA pool (in particular, a subframe pool for SA), through sensing.Also, the UE may autonomously determine a resource block from the SApool (particularly, a resource block pool for SA); this resource blockis a resource in the frequency domain used for the transmission of theSA in the subframe where the SA is transmitted. Therefore, unlike theeNodeB resource scheduling mode (mode 3), the UE may not receive the“CIF” and “Lowest index of sub-channel allocation” signaling field froman eNodeB through DCI, but may autonomously determine the same.

In addition, in the UE autonomous resource selection mode (mode 4), theUE may autonomously determine content related to Sidelink Controlinformation (SCI) as information (Scheduling Assignment (SA)) requiredwhen the UE transmits data in V2X. Therefore, unlike in the eNodeBresource scheduling mode (mode 3), the UE does not receive a first field(e.g., “Time gap between transmission and retransmission”) and a secondfield (e.g., “Frequency resource of initial and last transmission”) froman eNodeB through DCI, but may autonomously determine the same.

That is, the Sidelink Control information (SCI), which corresponds tothe information (Scheduling Assignment (SA)) required when the UEtransmits data, is determined based on information that the eNodeBtransmits to the UE in the eNodeB resource scheduling mode (mode 3), andthat is autonomously determined by the UE in the UE autonomous resourceselection mode (mode 4).

In both the eNodeB resource scheduling mode (mode 3) and the UEautonomous resource selection mode (mode 4), a UE (UE B) that receivesdata needs SCI corresponding to control information (SchedulingAssignment (SA)) in order to decode the data transmitted from the UE (UEA) that transmits the data. Therefore, a UE A is required to transmitthe SCI corresponding to the control information SA to the UE (UE B)that receives the data. As an example, the SCI may include informationas listed in Table 6.

TABLE 6 SCI for V2X Priority: 3 bits Resource reservation: 4 bits MCS: 5bits CRC: 16 bits Retransmission index: 1 bit Time gap betweentransmission and retransmission: 4 bits Frequency resource of initialand last transmission: 8 bits Reserved bits: 7 bits

Next, information included in DCI of Table 5 and SCI of Table 6 will bedescribed in detail.

As described above, information associated with a resource block that isa resource in the frequency domain used for SA transmission in theeNodeB resource scheduling mode (mode 3) may be indicated by beingincluded in DCI, and the information may be the “CIF” and the “Lowestindex of sub-channel allocation” signaling field mentioned in Table 5.

The “CIF” signaling field may have a size of 3 bits, and indicates acarrier (band) to be used for V2X. As an example, when a total of 5carriers are allowed for the UE, an indicator distinguishing betweeneach carrier may have the size of 3 bits (i.e., ceil(log2(5))=3, here,ceil(x) is the minimum integer which is greater than or equal to x). Theindicator may indicate which of the 5 carrier should be used for SAtransmission.

The “Lowest index of sub-channel allocation” signaling field mayindicate a resource block in a carrier (or band) for V2X, which is to beused for SA transmission, in a subframe in which SA is transmitted.

The “Lowest index of sub-channel allocation” signaling field mayindicate the sub-channel with the lowest index in sub-channels used forthe transmission of data related to the SA, from among a total of Ksub-channels having indices 0 to K-1. To this end, ceil(log2(K)) bitsmay be needed. The value of K is variable based on the size of a systembandwidth. For example, the maximum value of K may be 20. Accordingly, aminimum of 0 bits to a maximum of 5 bits may be used for the “Lowestindex of sub-channel allocation” field.

For example, when a total of six sub-channels having indices 0 to 5exist, and a PSSCH is allocated to a total of four sub-channelscorresponding to indices 2 to 5 from among the six sub-channels and whenthe PSSCH is used for the transmission of data related to the SA, thevalue indicated by “Lowest index of sub-channel allocation” may be index2. To indicate this value, a total of 3 (ceil(log2(6))) bits are needed.

In this instance, when a PSCCH for transmitting SA is adjacent to aPSSCH for transmitting data in the frequency domain, the PSCCH fortransmitting SA may be allocated in the RB with the lowest RB index inthe sub-channel indicated by “Lowest index of sub-channel allocation”.When a PSCCH for transmitting SA is not adjacent to a PSSCH fortransmitting data in the frequency domain, the PSCCH for transmitting SAmay be allocated in an RB that one-to-one matches the sub-channelindicated by “Lowest index of sub-channel allocation” (see the diagramon the right of FIG. 6).

As an example, it is assumed that the index value indicated by “Lowestindex of sub-channel allocation” is index 2. In this instance, when aPSCCH for transmitting SA and a PSSCH for transmitting data are adjacentin the frequency domain, the PSCCH for transmitting SA may be allocatedto the RB with the lowest RB index in a sub-channel corresponding toindex 2 (e.g., an RB corresponding to r+2* “sub-channel size” when an RBindex corresponding to “Starting RB of sub-channels” is r as shown inthe diagram on the left of FIG. 6). Alternatively, when a PSCCH fortransmitting SA and a PSSCH for transmitting data are not adjacent inthe frequency domain, the PSCCH for transmitting SA may be allocated toan RB that one-to-one matches a sub-channel corresponding to index 2(e.g., an RB corresponding to s+2 when an RB index corresponding to“Starting RB of PSCCH pool” is s as shown in the diagram on the right ofFIG. 6).

Subsequently, a first field (e.g., “Time gap between transmission andretransmission”) and a second field (e.g., “Frequency resource ofinitial and last transmission”) for indicating a resource used for aPSSCH for transmitting data among the SA contents in Table 5, may beincluded in DCI in the eNodeB resource scheduling mode (mode 3). Also,in the case of a first field (e.g., “Time gap between transmission andretransmission”) and a second field (e.g., “Frequency resource ofinitial and last transmission”) taken from Table 6, a value indicatedthrough DCI is included in SCI in the eNodeB resource scheduling mode(mode 3). However, in the UE autonomous resource selection mode (mode4), the UE determines the values based on a resource that the UEautonomously selects through sensing.

The first field (e.g., “Time gap between transmission andretransmission”) may indicate a gap between a subframe in whichTB-unit-based data related to SA is initially transmitted and a subframein which TB-unit-based data is retransmitted, or the first field mayindicate a gap between a subframe in which TB-unit-based data related tothe SA is initially transmitted and a subframe in which the SA isretransmitted. The value may be a value in the range of 0 to 15. A valueof 0 indicates that the retransmission of a TB does not exist, which isindicated through SA including the SCI and is transmitted. When thevalue is in the range of 1 to 15, this indicates that a TB, which hasbeen indicated through SA including the SCI and has been initiallytransmitted, should be retransmitted after 1 to 15 subframes elapses.For example, in the UE autonomous resource selection mode (mode 4), thefirst field (e.g., “Time gap between transmission and retransmission”)may indicate a gap between a subframe corresponding to “TTI m+d (=TTIm+c)” and a subframe corresponding to “TTI m+e” as shown in FIG. 7.

Subsequently, the second field (e.g., “Frequency resource of initial andlast transmission”) may indicate RBs in the frequency domain, which areused for transmission in a subframe in which the TB-unit-based data isinitially transmitting and in a subframe in which the TB-unit-based datais retransmitted. Additionally, the second field (e.g., “Frequencyresource of initial and last transmission”) may indicate informationassociated with sub-channels used for the initial transmission of data(the number of sub-channels used for the retransmission of data is equalto the number of sub-channels used for the initial transmission), andmay indicate information associated with the lowest index amongsub-channels used for the retransmission of data.

More particularly, when a TB is indicated through SA including the SCIand is initially transmitted, the lowest index among indices ofsub-channels used for the initial transmission may be indicated by the“Lowest index of sub-channel allocation” signaling field in the eNodeBresource scheduling mode (mode 3), and may be autonomously determined byan UE in the UE autonomous resource selection mode (mode 4). Here,information indicating the number of sub-channels to be used for thetransmission may be included in the second field (e.g., “Frequencyresource of initial and last transmission”).

In addition, when a TB is indicated through SA including the SCI and isretransmitted, the lowest index among indices of the sub-channels usedfor the retransmission may also be included in the second field (e.g.,“Frequency resource of initial and last transmission”). Informationindicating the number of sub-channels to be used for TB retransmissionmay be indicated by the second field (e.g., “Frequency resource ofinitial and last transmission”), and as many sub-channels as the numberof sub-channels which have been used for the initial transmission of theTB may be used.

For example, in the UE autonomous resource selection mode (mode 4), RBsfor transmitting a PSSCH in a subframe corresponding to “TTI m+d (=TTIm+c)” and a subframe corresponding to “TTI m+e” may be indicated by thesecond field (e.g., “Frequency resource of initial and lasttransmission”).

For the second field (e.g., “Frequency resource of initial and lasttransmission”), a total of ceil(log2(K*(K+1)/2) bits may be used on theassumption of K sub-channels. For example, because the maximum value ofK is 20, a minimum of 0 bit to a maximum of 8 bits may be needed.

Among other signaling fields included in the SCI of Table 6, “Priority”may indicate the priority of TB-unit-based data which is desired to betransmitted.

As described above, “Resource reservation” may indicate j ∈{0, 1, 2, . .. , 10}, which is a parameter used for indicating a reserved resource inthe UE autonomous resource selection mode (mode 4).

“Modulation and Coding Scheme” (MC S) may indicate the modulation schemeand coding scheme of TB-unit-based data which should be transmitted.

“Retransmission index” may indicate whether the retransmission ofTB-unit-based data exists.

“Cyclical Redundancy Check (CRC)” may be added to SCI and may be usedfor detecting an error when the SCI is transmitted and/or fordistinguishing the SCI from another SCI.

Next, examples of the present disclosure associated with a resource poolfor V2X communication will be described. More specifically, in theeNodeB resource scheduling mode (mode 3) or in the UE autonomousresource selection mode (mode 4), the process whereby a UE determines asubframe pool, and information (configuration) which is provided from aneNodeB to a UE for the determination of the subframe pool, will bedescribed.

FIG. 10 is a diagram illustrating the configuration of a subframe poolwithin a predetermined period.

FIG. 10 illustrates a set of all subframes belonging to a predeterminedperiod. For example, the predetermined period may be an SFN period or aDFN period (10240 ms). Because the time length of one subframe is lms, atotal of 10240 subframes (i.e., subframe indices #0 to #10239) may beincluded in the predetermined period.

The subframes remaining after excluding or skipping predeterminedsubframe(s) from the universal set of the subframes in the predeterminedperiod may be expressed as t^(SL) _(i) (0≦i≦Tmax). That is, thesubframes corresponding to {t^(SL) ₀, t^(SL) ₁, . . . , t^(SL)_(Tmax-1)} may be a set of subframes which may belong to a resource poolfor V2X communication. In the set of subframes {t^(SL) ₀, t^(SL) ₁, . .. , t^(SL) _(Tmax-1)}, subframes may be arranged in ascending order ofthe subframe indices from subframe #0 of a radio frame corresponding toSFN 0l (in mode 3) or DFN 0 (in mode 4) of a serving cell.

That is, the subframes corresponding to {t^(SL) ₀, t^(SL) ₁, . . . ,t^(SL) _(Tmax-1)} may be a set of subframes which may belong to aresource pool for V2X communication. Here, the subframes themselves,which correspond to {t^(SL) ₀, t^(SL) ₁, . . . , t^(SL) _(Tmax-1)} donot indicate a resource pool, but a part or all of them may beconfigured as a resource pool.

The universal set of the subframes in the predetermined period may bereferred to as a target subframe set to which a bitmap indicating aresource pool is applied (specifically, a subframe pool corresponding tothe time domain of the resource pool). Here, the predeterminedsubframe(s) may correspond to, for example, a subframe in which an SLSSresource is configured, a TDD DL subframe, a special subframe, and/or abitmap-non-applied-subframe (which will be described in detail later),and the like.

The bitmap associated with the resource pool may be expressed as {b₀,b₁, . . . , b_(Lbitmap-1)}. Here, L_(bitmap) denotes the length of thebitmap, which is set by a higher layer. The value of L_(bitmap) may be16, 20, or 100, but is not limited thereto. If L_(bitmap) is set to avalue smaller than the number of subframes belonging to thepredetermined period, the bitmap may be repeatedly applied within thepredetermined period.

A subframe pool may be configured with subframes corresponding to avalue of 1 indicated by the bitmap. That is, subframes corresponding tot^(SL) _(k) (here, 0≦k≦(10240-x-y)) may belong to a subframe pool whenb_(k)′=1 (here, k′=k mod L_(bitmap); mod indicates a modulo operation).That is, the subframe pool may include subframes that satisfy b_(k)′=1among t^(SL) _(k) when k′=k mod L_(bitmap).

Here, x may correspond to the number of subframes in which an SLSS isconfigured within the predetermined period. For example, the value of xmay be 0 or 64. When a period for configuring an SLSS is 160 ms, 64 SLSSsubframes may exist in a predetermined period having a length of 10240ms; therefore, x=64. Alternatively, when an SLSS is not configured, x=0.In the present disclosure, x SLSS-configured-subframes may be referredto as first-type-excluded-subframes.

In addition, y corresponds to the number of bitmap-non-applied-subframesin the predetermined period. As an example, the value of y may be 0, 16,40, or 76. Here, the bitmap-non-applied-subframe may be determined basedon the length of a predetermined period, the length of the bitmap, asubframe in which V2X transmission is reserved, or the like. Detailedexamples for these cases will be described later. In the presentdisclosure, y bitmap-non-applied-subframes may be referred to assecond-type-excluded-subframes.

When SA and/or data transmission is scheduled (or granted) in a subframet^(SL) _(m) in the resource pool determined as described above, SAand/or data transmission may be reserved in a subframe t^(SL) _(m+Prsvp)*j after P_(rsvp)*j elapses from t^(SL) _(m). Here, it is defined thatj=1, 2,. . . , C_(resel)-1. In this instance, C_(resel) may beC_(resel)=A*SL_RESOURCE_RESELECTION_COUNTER related to a resourcereselection counter.

For example, A=6 or 10, and the maximum value ofSL_RESOURCE_RESELECTION_COUNTER may be 15. P_(rsvp) is a resourcereservation interval set by a higher layer. For example, 100 may befixedly used as P_(rsvp), or one selected from among 100 and one or moreother values may be selected and used as P_(rsvp).

For example, there is a scenario where P_(rsvp)=100, Tmax=10240, andj=1, 2, . . . , 149. Also, the length of a bitmap is 100, the value of afirst bit is 1, and the value of a 61^(th) bit is 0 (i.e., a subframepool includes subframe #0 but does not include subframe #60). Also, theindex of a first subframe in which SA and/or data transmission isscheduled, in the subframe pool, is #0. In this instance, subframeindices #0, #100, #200, . . . , and #10200 of a first period andsubframe indices #60, #160, . . . , and #4760 of a second period may bereserved. Here, one period includes indices up to #10239, a subframecorresponding to #10300, which is reserved after #10200, may be #60 ofthe second period.

As described above, the case in which a resource is reserved beyond onepredetermined period (e.g., an SFN period or a DFN period) may beexpressed as an SFN (or DFN) wrap-around situation in resourcereservation. When Tmax is indivisible by L_(bitmap) (i.e., when thenumber of subframes included in the set of subframes to which a bitmapis to be applied is not an integer multiple of the length of thebitmap), only a part of the bitmap (i.e., only a front part of thebitmap) is applied in the last part of the first period, and the bitmapis newly and repeatedly applied in the second period. In this instance,in the second period, the subframes #60, #160, #260, . . . and the likemay not be included in a subframe pool according to the bitmap. However,SA and/or data transmission/reception is reserved. Accordingly, theremay be ambiguity. This may be called ambiguity attributable to SFN (orDFN) wrap-around.

To avoid ambiguity attributable to SFN (or DFN) wrap-around, tone ormore of: the number of bitmap-non-applied-subframes y (or the number ofsecond-type-excluded-subframes) and the pattern ofbitmap-non-applied-subframes, a resource reservation interval P_(rsvp)configuration, and/or restriction on the maximum value of a resourcereservation multiple parameter j may be applied in the system describedabove. Next, detailed examples of the present disclosure will bedescribed.

FIG. 11 is a flowchart illustrating a method of determining a resourcepool.

In the example of FIG. 11, a first UE and a second UE correspond to UEsthat join in V2X communication or direct link communication, wherein thefirst UE corresponds to an SA and data transmission (Tx) UE, and thesecond UE corresponds to an SA and data reception (Rx) UE.

In operation S1110, an eNodeB may transmit, to the first UE, resourcepool configuration information for V2X communication, SLSS configurationinformation, and the like. For example, the eNodeB may transmit theinformation through higher layer signaling. Here, the resource poolconfiguration information may correspond to “subframe indication ofresource pool” information including a bitmap having a length ofL_(bitmap). In addition, the SLSS configuration information maycorrespond to “SL V2V synchronization configuration” information (i.e.,configuration information associated with whether a UE transmits andreceives synchronization information associated with a sidelink forV2V).

In operation S1120, the first UE may determine xfirst-type-exclude-subframes (i.e., subframes in which an SLSS resourceis configured) based on the SLSS configuration information. Accordingly,the x first-type-exclude-subframes may be excluded from a set of allsubframes belonging to a predetermined period (e.g., 10240 subframeswhich correspond to all subframes in a single SFN (or DFN) period).Here, the set of subframes remaining after excluding the xfirst-type-exclude-subframes from the set of all subframes may bereferred to as a first subset. For example, x=0 or 64.

In operation S1130, the first UE may determine asecond-type-exclude-subframe (i.e., an additionalbitmap-non-applied-subframe) by taking into consideration the firstsubset, L_(bitmap), and the like determined in operation S1120.Particularly, the first UE may determine whether to additionally excludethe second-type-exclude-subframe. When needed, the UE may determine thenumber of second-type-exclude-subframes. Accordingly, ysecond-type-exclude-subframes may be excluded from the first subset, andthe result may be referred to as a second subset. For example, y=0, 16,40, or 76.

In operation S1140, the first UE may repeatedly apply the bitmap havinga length of L_(bitmap) to the second subset which has been determined bytaking into consideration the first-type-exclude-subframes and thesecond-type-exclude-subframes. According to the present disclosure, thenumber of subframes of the second subset may be a multiple ofL_(bitmap), whereby ambiguity attributable to the above described SFN(or DFN) wrap-around may not occur.

Operation S1145 is performed when the first UE is set to operate in theeNodeB resource scheduling mode (mode 3), and is omitted when the firstUE is set to operate in the UE autonomous resource selection mode (mode4). In operation S1145, the first UE receives, from the eNodeB, DCIincluding scheduling information (or grant information) of SA and/ordata transmission.

In operation S1150, when the first UE is set to operate in the eNodeBresource scheduling mode (mode 3), the first UE may determine a resource(e.g., a subframe and a sub-channel) to be used for transmitting SAand/or data to the second UE, based on the DCI received from the eNodeB.When the first UE is set to operate in the UE autonomous resourceselection mode (mode 4), the first UE may autonomously determine aresource to be used for transmitting SA and/or data to the second UE.For example, the first UE may determine a resource through which SAand/or data is to be transmitted, by taking into consideration the stateof channel occupancy by a sensing window in a predetermined period priorto the point in time when a TB to be transmitted to the second UE hasbeen generated.

In operation S1160, the first UE determines a resource reservationinterval (P_(rsvp)) and a resource reservation multiple parameter (j),and may determine transmission-reservation-subframes based thereon.

For example, a fixed value (e.g., P_(rsvp)=100) may be used as P_(rsvp),or one selected from among a plurality of values may be used asP_(rsvp). In this instance, when a value selected from among theplurality of values is used, P_(rsvp) may be directly indicated byhigher layer signaling. P_(rsvp) may be determined in connection withL_(bitmap), or P_(rsvp) may be determined based on informationassociated with whether a short resource reservation period is used andL_(bitmap).

When one fixed value is always used as P_(rsvp), P_(rsvp) may always be100 irrespective of the value of L_(bitmap) (16, 20, or 100).

When one value selected from among a plurality of values is used asP_(rsvp), and P_(rsvp) is indicated directly by higher layer signaling,one value may be selected from among the plurality of values asP_(rsvp), irrespective of the value of L_(bitmap) (16, 20, or 100). Forexample, although either 25 (if the reservation period is short) or 100may be selected as the value, the value is not limited thereto.

When one value selected from among a plurality of values is used asP_(rsvp), and P_(rsvp) is determined in connection with L_(bitmap), thefirst UE may directly receive, from an eNodeB, the value of P_(rsvp)which is determined in connection with L_(bitmap) (or a value indicatinga combination of P_(rsvp) and L_(bitmap)), or the first UE mayautonomously determine the value of P_(rsvp) associated with the valueof L_(bitmap) based on the value of L_(bitmap) received in operationS1110.

As an example, the value of P_(rsvp) associated with the value ofL_(bitmap) may be determined as shown in Table 7 provided below. In thisinstance, when the value of P_(rsvp) is one of the values correspondingto multiples of 16 in Table 7, the value may be 16, 32, 96, or 112,wherein 16 and 32 are multiples of 16 that are close to 25 (if thereservation period is short), and 96 and 112 are multiples of 16 thatare close to 100. However, the value is not limited thereto.

TABLE 7 L_(bitmap) P_(rsvp) 100 100 20 100 16 One of valuescorresponding to multiples of 16

In this instance, one value selected from among a plurality of values isused as P_(rsvp), and P_(rsvp) is determined based on L_(bitmap) and oninformation associated with whether a short resource reservation periodis used. Then, the first UE may directly receive, from an eNodeB, thevalue of P_(rsvp) which is determined based on L_(bitmap) (or a valueindicating the combination of the information associated with whether ashort resource reservation period is used and L_(bitmap)) and on theinformation associated with whether a short resource reservation periodis used and L_(bitmap). Alternatively, the first UE may autonomouslydetermine the value of P_(rsvp) in association with information ofwhether a short resource reservation period is used and L_(bitmap) basedon the information associated with whether a short resource reservationperiod is used (information whether a short reservation period is usedor not may be indicated by the eNodeB through higher layer signalingsuch as RRC or the like) and L_(bitmap) received from the eNodeB inoperation S1110. For example, the value of P_(rsvp) in association withinformation of whether a short reservation period is used and the valueof L_(bitmap) may be determined as shown in Table 8 provided below. Whenthe value of P_(rsvp) is one of the values corresponding to multiples of16 in Table 8, the value may be one of 16 and 32 which are multiples of16 that are close to 25 when a short reservation period is used, and thevalue may be one of 96 and 112 which are multiples of 16 that are closeto 100 when a short reservation period is not used. However, the valueis not limited thereto.

TABLE 8 Short reservation period L_(bitmap) P_(rsvp) Not used 100 100Not used 20 100 Not used 16 One of values corresponding to multiples of16 Used 100  25 Used 20  25 Used 16 One of values corresponding tomultiples of 16

As described above, even when L_(bitmap)=16, 100 may be used as thevalue of P_(rsvp). However, in the case of L_(bitmap)=16, when a bitmaphaving a length of 16 bits is (b₀, b₁, b₂, . . . , b₁₅), P_(rsvp)=100.Accordingly, subframes in units of multiples of 100 may or may notbelong to a subframe pool together. That is, the bit values of (b₀, b₄,b₈, b₁₂) need to always be the same. In the same manner, the bit valuesof (b₁, b₅, b₉, b₁₃) need to always be the same, the bit values of (b₂,b₆, b₁₀, b₁₄) need to always be the same, and the bit values of (b₃, b₇,b₁₁, b₁₅) need to always be the same. This is merely a four-bit bitmaprepeated four times, as opposed to a 16-bit bitmap. Therefore, theconfiguration of a bitmap may be under restrictions.

Even if there are restrictions, in order to set the resource reservationinterval P_(rsvp) to be the same in all cases, the value of P_(rsvp),which is the same as the value of P_(rsvp) (e.g., P_(rsvp)=100) whenL_(bitmap)=20 or 100, may be used when L_(bitmap)=16.

Alternatively, to overcome the restrictions, with respect to 100subframes corresponding to P_(rsvp)=100, a bitmap (b₀, b₁, b₂, b₁₅)having a length of 16 in the case of L_(bitmap)=16, is applied six timesand only a part (b₀, b₁, b₂, b₃) is applied with respect to the lastfour subframes. With respect to the subsequent 100 subframes, the bitmap(b₀, b₁, b₂, b₁₅) having a length of 16 is applied six times; only thefront four bits (b₀, b₁, b₂, b₃) of the bitmap are applied with respectto the last four subframes, in the same manner as described above. Inthis manner, when a bitmap having a length of 16 is applied with respectto 10240 subframes included in a single SFN (or DFN) period based on a100-subframe unit, as described above, the above restriction may notexist. However, it is the same as the case in which a bit value isapplied based on a 100-subframe period. Therefore, ambiguityattributable to SFN (or DFN) wrap-around may occur, as in the case ofL_(bitmap)=20 or 100.

Therefore, in the case of L_(bitmap)=16, one of the multiples of 16 maybe set as P_(rsvp), as described above, to overcome the aboverestriction. In this instance, the restriction caused when P_(rsvp) isindivisible by L_(bitmap) may be overcome. At the same time, ambiguityattributable to SFN (or DFN) wrap-around may not be generated becausethe value10240 (corresponding to the total number of subframes in asingle SFN (or DFN) period) is divisible by the value 16 correspondingto L_(bitmap). However, in this instance, the resource reservationinterval P_(rsvp) must be set to be different from the case ofL_(bitmap)=20 or 100. Therefore, the number of events, which must betaken into consideration in a resource reservation process, may beincreased.

In operations S1170 and S1180, the first UE may map SA and data to theresource determined in operation S1150, and may transmit the same to thesecond UE. For example, in operation S1170, the first UE may transmit SAcorresponding to SCI to the second UE. Then in operation S1180, thefirst UE may transmit data to the second UE in a resource indicated bythe SCI transmitted in operation S1170.

In operation S1190, the second UE may attempt to receive the SA from thefirst UE according to a blind decoding scheme. The blind decoding schememay include monitoring the locations of candidate resources throughwhich SA may be received. Also, the second UE may determine a resourcein which data is to be received based on the SCI received from the firstUE, and may attempt to decode the data transmitted from the first UE.

Although the above described illustrative methods of FIG. 11 areexpressed as a series of operations, they do not limit the order ofoperations executed; the operations may be executed in parallel or in adifferent order. In order to implement the system described above,another operation may be added to the described operations, only theoperations remaining after excluding one or more operations may beincluded, or one or more operations may be excluded and additional otheroperations may be included.

Next, more detailed examples associated with FIG. 11 will be described.

One feature in FIG. 11 is that the number ofsecond-type-exclude-subframes (y) is taken into consideration. Inaddition, in the case of L_(bitmap)=16, one of the multiples of 16(e.g., 96) may be set as the value of P_(rsvp). Although above describedrestrictions may exist, 100 may be used as the value of P_(rsvp) in thecase of L_(bitmap)=16 (like the case of L_(bitmap)=20 or 100.) WhenP_(rsvp) is set as described above, ambiguity may be removed if an SFN(or DFN) wrap-around situation occurs, or the SFN (or DFN) wrap-aroundsituation may not occur.

x, L_(bitmap), and y according to the example of FIG. 11 may be set asshown in Table 9 provided below.

TABLE 9 x L_(bitmap) y 0 100 40 0 20 0 0 16 0 64 100 76 64 20 16 64 16 0

Referring to Table 9, concrete embodiments of the method of FIG. 11 willbe described.

Embodiment 1

This embodiment relates to the case in which L_(bitmap)=100 and x=0. Inthis instance, y=40, as shown in Table 9. Accordingly, a subframe poolis determined to be t^(SL) _(k) (here, 0≦k≦(10240-0-40)). That is, abitmap may be repeatedly applied to subframes (i.e., a second subset)remaining after excluding 40 subframes (y=40). In this instance, abitmap having a length of 100 is repeatedly applied to 10200 subframes,and thus, the number of target subframes to which the bitmap is to beapplied (i.e., Tmax) may be an integer multiple of the length of thebitmap (or the number of target subframes to which the bitmap is to beapplied is divisible by the length of the bitmap).

Next, examples of the pattern of 40 second-type-exclude-subframes (y=40)will be described.

Embodiment 1-1

40 second-type-exclude-subframes may exist at intervals of256(=10240/40) subframes. For example, subframe indices #255, #511, . .. . , and #10239 may correspond to second-type-exclude-subframes.

That is, subframes corresponding to subframe indices y_(n) in a singleSFN (or DFN) period may be the second-type-exclude-subframes. Here, itis defined that y_(n)=256*(n+1)-1 and, n=0, 1, . . . , 39.

Embodiment 1-2

40 second-type-exclude-subframes may be the last 40 subframes in 10240subframes in a single SFN (or DFN) period. For example, subframe indices#10201, #10202, . . . . , and #10240 may correspond to thesecond-type-exclude-subframes.

That is, subframes corresponding to subframe indices y_(n) in a singleSFN (or DFN) period may be the second-type-exclude-subframes. Here, itis defined that y_(n)=10240-n and, n=0, 1, . . . , 39.

Embodiment 2

This embodiment relates to the case in which L_(bitmap)=100 and x=64. Inthis instance, it is determined that y=76, as shown in Table 9.Accordingly, a subframe pool is determined to be t^(SL) _(k) (here,0≦k<(10240-64-76)). That is, a bitmap may be repeatedly applied tosubframes (i.e., a second subset) remaining after excluding subframescorresponding to x=64 and y=′76. In this instance, a bitmap having alength of 100 is repeatedly applied to 10100 subframes, and thus, thenumber of target subframes to which the bitmap is to be applied (i.e.,Tmax) may be an integer multiple of the length of the bitmap (or thenumber of target subframes to which the bitmap is to be applied isdivisible by the length of the bitmap).

Next, examples of the pattern of 72 second-type-exclude-subframes (y=72)will be described.

Embodiment 2-1

76 second-type-exclude-subframes may be one or two subframes followingafter first-type-exclude-subframes (i.e., SLSS transmission subframes).

For example, 64 second-type-exclude-subframes among the 76second-type-exclude-subframes (y=76) may be determined to be subframesimmediately after the 64 first-type-exclude-subframes (x=64) among 10240subframes included in a single SFN (or DFN) period. Additionally, the 12remaining second-type-exclude-subframes out of the 76 subframes (y=76)may be determined to be second following subframes which respectivelyfollow after 1^(st), 6^(th), 11^(th), 16^(th), 21^(st), 26^(th),31^(st), 36^(th), 41^(st), 46^(th), 51^(st), and 56^(th)first-type-exclude-subframes of the 64 first-type-exclude-subframes(x=64) among the 10240 subframes in a single SFN (or DFN) period.

That is, subframes corresponding to subframe indices y_(n) and y_(n2) ina single SFN (or DFN) period may be the second-type-exclude-subframes.

Here, it is defined that y_(n1)=x₀+160*n₁+1 and, n=0, 1, . . . , 63.Here, xo corresponds to an index of a first first-type-exclude-subframe(i.e., a subframe which an SLSS is initially transmitted) in a singleSFN (or DFN) period.

Here, it is defined that y_(n2)=x₀+800*n₂+2 and, n=0, 1, . . . , 11.

Embodiment 2-2

76 second-type-exclude-subframes may be the last 76 subframes of 10240subframes in a single SFN (or DFN) period.

When a first-type-exclude-subframe (i.e., an SLSS transmission subframe)does not exist between subframe index #10165 and subframe index #10240,subframe indices #10165, #10166, . . . , and #10240 may correspond tosecond-type-exclude-subframes.

That is, subframes corresponding to subframe indices y_(n) in a singleSFN (or DFN) period may be second-type-exclude-subframes. Here, it isdefined that y_(n)=10240-n and that n=0, 1, . . . , 75.

When a first-type-exclude-subframe (i.e., an SLSS transmission subframe)exists between subframe index #10165 and subframe index #10240, subframeindices #10164, #10165, . . . , and #10240 may correspond tosecond-type-exclude-subframes.

That is, subframes corresponding to subframe indices y_(n) in a singleSFN (or DFN) period may be second-type-exclude-subframes. Here, when10240-n>x₆₃, y_(n)=10240-n. Otherwise (i.e., when 10240-n≦x₆₃),y_(n)=10239-n and n=0, 1, . . . , 75. Here, x_(n) indicates afirst-type-exclude-subframe, and x₆₃ corresponds to a 64^(th)first-type-exclude-subframe.

Embodiment 2-3

76 second-type-exclude-subframes may be 64 subframes, which respectivelyfollow immediately after first-type-exclude-subframes (i.e., SLSStransmission subframes) and the last 12 subframes of 10240 subframes ina single SFN (or DFN) period.

For example, 64 second-type-exclude-subframes among 76 subframes (y=76)may be determined to be subframes which respectively follow immediatelyafter 64 first-type-exclude-subframes (x=64) of 10240 subframes in asingle SFN (or DFN) period. The second-type-exclude-subframes may beexpressed as subframe index y_(n1).

Additionally, when a first-type-exclude-subframe (i.e., an SLSStransmission subframe) does not exist between subframe index #10229 andsubframe index #10240, the remaining 12 second-type-exclude-subframes ofthe 76 subframes (y=76) may correspond to subframes corresponding toindices #10229, #10230, . . . , and #10240 in a single SFN (or DFN)period. When a first-type-exclude-subframe (i.e., an SLSS transmissionsubframe) exists between subframe index #10229 and subframe index#10240, subframe indices #10227, #10228, . . . , and #10240 maycorrespond to second-type-exclude-subframes. Thesecond-type-exclude-subframes may be expressed as a subframe indexy_(n1).

That is, subframes corresponding to subframe indices y_(n) and y_(n2) ina single SFN (or DFN) period may be the second-type-exclude-subframes.

Here, y_(n1)=x₀+160*n₁+1, and n=0, 1, . . . , 63, where x₀ correspondsto an index of a first first-type-exclude-subframe (i.e., a subframe inwhich an SLSS is initially transmitted) in a single SFN (or DFN) period.

Also, subframes corresponding to subframe indices y_(n2) in a single SFN(or DFN) period may be the second-type-exclude-subframes. Here, it isdefined that y_(n2)=10240-n₂ and, n=0, 1, . . . , 11.

Alternatively, subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,when 10240-n₂>x₆₃, y_(n)=10240-n₂. Otherwise (i.e., when 10240-n₂≦x₆₃),y_(n)=10238-n₂ and n₂=0, 1, . . . , 11. Here, x_(n) indicates afirst-type-exclude-subframe, and x₆₃ corresponds to a 64^(th)first-type-exclude-subframe.

Embodiment 3

The present embodiment relates to the case in which L_(bitmap)=20 andx=0. In this instance, y=0, as shown in Table 9. Accordingly, a subframepool is determined to be t^(SL) _(k) (here, 0≦k<(10240-0-0)). That is, afirst-type-exclude-subframe and a second-type-exclude-subframe may notexist, and a bitmap may be repeatedly applied to all subframes in apredetermined period. In this instance, a bitmap having a length of 20is repeatedly applied to 10240 subframes, and thus, the number of targetsubframes to which the bitmap is to be applied (i.e., Tmax) may be aninteger multiple of the length of the bitmap (e.g., the number of targetsubframes to which the bitmap is to be applied is divisible by thelength of the bitmap).

Embodiment 4

The present embodiment relates to the case in which L_(bitmap)=20 andx=64. In this instance, y=16, as shown in Table 9. Accordingly, asubframe pool is determined to be t^(SL) _(k) (here, 0≦k<(10240-64-16)).That is, a bitmap may be repeatedly applied to subframes (i.e., a secondsubset) remaining after excluding subframes corresponding to x=64 andy=16. In this instance, a bitmap having a length of 20 is repeatedlyapplied to 10160 subframes, and thus, the number of target subframes towhich the bitmap is to be applied (i.e., Tmax) may be an integermultiple of the length of the bitmap (e.g., the number of targetsubframes to which the bitmap is to be applied is divisible by thelength of the bitmap).

Next, examples of a pattern of 16 second-type-exclude-subframes (y=16)will be described.

Embodiment 4-1

16 second-type-exclude-subframes may be subframes that respectivelyfollow after some of first-type-exclude-subframes (i.e., SL SStransmission subframes).

For example, the 16 remaining second-type-exclude-subframes (y=16) maybe determined to be subframes which respectively follow immediatelyafter the 1^(st), 5^(th), 9^(th), 13^(th), 17^(th), 21^(st), 25^(th),29^(th), 33^(th), 37^(th), 41^(st), 45^(th), 49^(th); 53^(th), 57^(th),and 61^(st) first-type-exclude-subframes among 64first-type-exclude-subframes (x=64) of the 10240 subframes in a singleSFN (or DFN) period.

That is, subframes corresponding to subframe indices y_(n) in a singleSFN (or DFN) period may be second-type-exclude-subframes. Here, it isdefined that y_(n)=x₀+640*n+1 and, n=0, 1, . . . , 15. Here, xocorresponds to an index of the first first-type-exclude-subframe (i.e.,a subframe in which an SLSS is initially transmitted) in a single SFN(or DFN) period.

Embodiment 4-2

16 second-type-exclude-subframes may be the last 16 subframes of 10240subframes in a single SFN (or DFN) period.

When a first-type-exclude-subframe (i.e., an SLSS transmission subframe)does not exist between subframe index #10225 and subframe index #10240,subframe indices #10225, #10226, . . . , and #10240 may correspond tosecond-type-exclude-subframes.

That is, the subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,it is defined that y_(n)=10240-n and n=0, 1, . . . , 15.

When a first-type-exclude-subframe (i.e., an SLSS transmission subframe)exists between subframe index #10225 and subframe index #10240, subframeindices #10224, #10225, . . . , and #10240 may correspond tosecond-type-exclude-subframes.

That is, the subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,when 10240-n>x₆₃, y_(n)=10240-n. Otherwise (i.e., when 10240-n≦x₆₃),y_(n)=10239-n and n=0, 1, . . . , 15. Here, x_(n) indicates afirst-type-exclude-subframe, and x₆₃ indicates a 64^(th)first-type-exclude-subframe.

The embodiments 1 through 4 which are detailed embodiments of the methodof FIG. 11 may additionally include features described in the followingembodiments A or B, or the features corresponding to the embodiments 1through 4 may be replaced with the features described in embodiments Aor B.

Embodiment A

As described above, in operation S1120, the first UE may determine xfirst-type-exclude-subframes (i.e., subframes in which an SLSS resourceis configured) based on the SLSS configuration information. Accordingly,the x first-type-exclude-subframes may be excluded from a set of allsubframes belonging to a predetermined period (e.g., 10240 subframeswhich correspond to all subframes in a single SFN (or DFN) period).Here, the set of subframes remaining after excluding the xfirst-type-exclude-subframes from the set of all subframes may bereferred to as a first subset. For example, x=0 or 64.

Subsequently, in operation S1130, the first UE may determine asecond-type-exclude-subframe (i.e., an additionalbitmap-non-applied-subframe) by taking into consideration the firstsubset, L_(bitmap), and the like which have been determined in operationS1120. More specifically, the first UE determines whether toadditionally exclude the second-type-exclude-subframe. When needed, theUE may determine the number of second-type-exclude-subframes.Accordingly, y second-type-exclude-subframes may be excluded from thefirst subset, and the result may be referred to as a second subset. Forexample, y=0, 16, 40, or 76.

Embodiment A-1

In the case of y=0 (in this instance, (X, L_(bitmap)) is (0, 20), (0,16) or (64, 16) as shown in Table 9), y second-type-exclude-subframes(which are additionally reserved subframes that are not included in asubframe pool or that are not considered to be a subframe pool) do notexist when a subframe pool is configured by repeatedly applying a bitmaphaving a length of L_(bitmap) in operation S1140. Accordingly, thelocations of the y second-type-exclude-subframes may need to be defined.

Embodiment A-2

In the case of y=40 (in this instance, (X, L_(bitmap)) is (0, 100) asshown in Table 9), when a subframe pool is configured by repeatedlyapplying a bitmap having a length of L_(bitmap) in operation 1140, 40subframes may need to be defined as y second-type-exclude subframes,which are additionally reserved (i.e., subframes that are not includedin a subframe pool or subframes that are not considered to be a subframepool).

In this instance, the 40 second-type-exclude-subframes may exist atintervals of 256(=10240/40) subframes. For example, subframe indices #d,#(d+256), #(d+512), . . . . , and #(d+9984) may correspond to thesecond-type-exclude-subframes. In this instance, d is an integer thatsatisfies 0≦d<256.

That is, subframes corresponding to subframe indices y_(n) in a singleSFN (or DFN) period may be second-type-exclude-subframes. Here, it isdefined that y_(n)=d+256*n and n=0, 1, . . . , 39. One of the integervalues that satisfies 0≦d<256 may be selected as d. For example, d maybe 255 (d=255), but it is not limited thereto.

Embodiment A-3

In the case of y=76 (in this instance, (X, L_(bitmap)) is (64, 100) asshown in Table 9), when a subframe pool is configured by repeatedlyapplying a bitmap having a length of L_(bitmap) in operation 1140, 76subframes may need to be defined as y second-type-exclude-subframes,which are additionally reserved (i.e., subframes that are not includedin a subframe pool or subframes that are not considered to be a subframepool).

In this instance, the 76 second-type-exclude-subframes may exist atintervals of D subframes. For example, subframe indices #d, #(d+D),#(d+2D), . . . . , and #(d+75*D) may correspond to thesecond-type-exclude-subframes. In this instance, d is an integer thatsatisfies 0≦d<D. In this instance, the interval D may be 134, which isobtained by dividing 10240 by 76 (i.e., int(10240/76)), whereby 76second-type-exclude-subframes are evenly distributed over a total of10240 subframes. However, the value is not limited thereto.

In this instance, when a second-type-exclude-subframe which isdetermined as described above overlaps a first-type-exclude-subframe(i.e., a subframe in which an SLSS is transmitted), that is, when thesecond-type-exclude-subframe has the same subframe index as that of thefirst-type-exclude-subframe, only with respect to thesecond-type-exclude-subframe that overlaps thefirst-type-exclude-subframe (the subframe in which SLSS transmission isperformed), a subframe which is d′ distant away from the subframecorresponding to the subframe index determined as described above may bedetermined to be a second-type-exclude-subframe. In this instance,1≦d′<D. That is, in the case of d′=1, a subframe that overlaps afirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed) may not be defined as a second-type-exclude-subframe;however, a subsequent subframe may be defined as asecond-type-exclude-subframe.

In other words, subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,it is defined that y_(n)=d+D*n and n=0, 1, . . . , 75. One of theinteger values that satisfy 0≦d<D may be selected as d. For example, dmay be 133 (d=133), but it is not limited thereto. Also, D may beint(10240/76)=134, but it is not limited thereto. When asecond-type-exclude-subframe defined by y_(n)=d+D*n overlaps afirst-type-exclude-subframe (a subframe in which SLSS transmission isperformed), a subframe that is d′ subframes away from the correspondingsecond-type-exclude-subframe may be a second-type-exclude subframe, and1≦d′<D. In this instance, d′ may be 1 (d′=1), but it is not limitedthereto.

Embodiment A-4

In the case of y=16 (in this instance, (X, L_(bitmap)) is (64, 20) asshown in Table 9), when a subframe pool is configured by repeatedlyapplying a bitmap having a length of L_(bitmap) in operation 1140, 16subframes may need to be defined as y second-type-exclude-subframes,which are additionally reserved subframes (i.e., subframes that are notincluded in a subframe pool or subframes that are not considered to be asubframe pool).

In this instance, the 16 second-type-exclude-subframes may exist atintervals of 640(=10240/16) subframes. For example, subframe indices #d,#(d+640), #(d+1280), . . . . , and #(d+9600) may correspond to thesecond-type-exclude-subframes. In this instance, d is an integer thatsatisfies 0≦d<640.

In this instance, when a second-type-exclude-subframe determined asdescribed above overlaps a first-type-exclude-subframe (i.e., a subframein which an SLSS is transmitted), that is, when thesecond-type-exclude-subframe has the same subframe index as that of thefirst-type-exclude-subframe, only with respect to thesecond-type-exclude-subframe that overlaps thefirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed), a subframe which is d′ distant away from the subframecorresponding to the subframe index determined as described above may bedetermined to be a second-type-exclude-subframe. In this instance,1≦d′<640. That is, in the case of d′=1, when a subframe overlaps afirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed), it may not be defined as a second-type-exclude-subframe;however, a subsequent subframe may be defined as asecond-type-exclude-subframe.

In other words, subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,it is defined that y_(n)=d+640*n and n=0, 1, . . . , 15. One of theinteger values that satisfies 0≦d<640 may be selected as d. For example,d may be 639 (d=639), but it is not limited thereto. When asecond-type-exclude-subframe defined by y_(n)=d+D*n overlaps afirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed), a subframe that is d′ subframes away from thecorresponding second-type-exclude-subframe may be a second-type-excludesubframe, and 1≦d′<640. In this instance, d′ may be 1 (d′=1), but it isnot limited thereto.

According to the above described embodiments A-2 to A-4, when y isdifferent from 0 and when y second-type-exclude-subframes therefore needto be defined, the locations of the second-type-exclude-subframes may bedetermined as follows.

The y second-type-exclude-subframes may exist at intervals of Dsubframes. For example, subframe indices #d, #(d+D), #(d+2D), . . . . ,and #(d+(y-1)*D) may correspond to the second-type-exclude-subframes. Inthis instance, d is an integer that satisfies 0≦d<D, where the intervalD is a value which is obtained by dividing 10240 by y (i.e.,int(10240/y)), whereby the y second-type-exclude-subframes are evenlydistributed over a total of 10240 subframes.

In this instance, when a second-type-exclude-subframe which isdetermined as described above overlaps a first-type-exclude-subframe(i.e., a subframe in which an SLSS is transmitted), that is, when thesecond-type-exclude-subframe has the same subframe index as that of thefirst-type-exclude-subframe), only with respect to thesecond-type-exclude-subframe that overlaps thefirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed), a subframe which is d′ distant away from the subframecorresponding to the subframe index determined as described above may bedetermined to be a second-type-exclude-subframe. In this instance,1≦d′<D. That is, in the case of d′=1, when a subframe overlaps afirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed), it may not be defined as a second-type-exclude-subframe,but a subsequent subframe may be defined as asecond-type-exclude-subframe.

In other words, subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,it is defined that y_(n)=d+D*n and n=0, 1,. . . , y-1. One of theinteger values that satisfies 0≦d<D may be selected as d. For example, dmay be D-1 (d=D-1), but it is not limited thereto. Also, D may beint(10240/y), but it is not limited thereto. When asecond-type-exclude-subframe defined by y_(n)=d+D*n overlaps afirst-type-exclude-subframe (i.e., a subframe in which SLSS transmissionis performed), a subframe that is d′ subframes away from thecorresponding second-type-exclude-subframe may be a second-type-excludesubframe, and 1≦d′<D. In this instance, d′ may be 1 (d′=1), but it isnot limited thereto.

Embodiment B

In addition to Frequency Division Duplexing (FDD), embodiment B takesTime Division Duplexing (TDD) into consideration as a duplexing scheme.

When using TDD, Table 9 may be replaced with Table 10 as shown below.

TABLE 10 Duplexing Z x L_(bitmap) y FDD 10240 0 100 40 0 20 0 0 16 0 64100 76 64 20 16 64 16 0 TDD 6144 0 100 44 UL-DL 0 20 4 configuration 016 0 0 64 100 80 64 20 0 64 16 0 TDD 4096 0 100 96 UL-DL 0 20 16configuration 0 16 0 1 64 100 32 64 20 12 64 16 0 TDD 2048 0 100 48UL-DL 0 20 8 configuration 0 16 0 2 64 100 84 64 20 4 64 16 0 TDD 3072 0100 72 UL-DL 0 20 12 configuration 0 16 0 3 64 100 8 64 20 8 64 16 0 TDD2048 0 100 48 UL-DL 0 20 8 configuration 0 16 0 4 64 100 84 64 20 4 6416 0 TDD 1024 0 100 24 UL-DL 0 20 4 configuration 0 16 0 5 64 100 60 6420 0 64 16 0 TDD 5120 0 100 20 UL-DL 0 20 0 configuration 0 16 0 6 64100 56 64 20 16 64 16 0

In operation S1120, as described above, a first UE may determine xfirst-type-exclude-subframes (i.e., subframes in which an SLSS resourceis configured) based on the SLSS configuration information. Accordingly,x first-type-exclude-subframes may be excluded from a set of all uplinksubframes included in a predetermined period (e.g., z subframescorresponding to all uplink subframes included in a single SFN (or DFN)period (z may change according to the FDD and TDD UL-DL configuration asshown in Table 10)). Here, the set of subframes remaining afterexcluding the x first-type-exclude-subframes from the set of allsubframes may be referred to as a first subset. For example, x=0 or 64.

Subsequently, in operation S1130, the first UE may determine asecond-type-exclude-subframe (i.e., an additionalbitmap-non-applied-subframe) by taking into consideration the firstsubset, L_(bitmap), and the like determined in operation S1120. Here,the first UE determines whether to additionally exclude thesecond-type-exclude-subframe. When needed, the first UE may determinethe number of second-type-exclude-subframes. Accordingly, ysecond-type-exclude-subframes may be excluded from the first subset, andthe result may be referred to as a second subset. For example, y may bea value corresponding to each case of Table 10.

In the case of y=0, when a subframe pool is configured by repeatedlyapplying a bitmap having a length of L_(bitmap) in operation 1140, ysecond-type-exclude-subframes, which in this case are additionallyreserved subframes (i.e., subframes that are not included in a subframepool or subframes that are not considered to be a subframe pool), do notexist. Thus, there is no need to define the locations of the ysecond-type-exclude-subframes.

When y is different from 0 and y second-type-exclude-subframes need tobe defined, the locations of the y second-type-exclude-subframes may bedetermined as follows.

The y second-type-exclude-subframes may exist at intervals of Dsubframes. For example, subframe indices #d, #(d+D), #(d+2D), . . . . ,and #(d+(y-1)*D) may correspond to the second-type-exclude-subframes. Inthis instance, d is an integer that satisfies 0≦d<D. In this instance,the interval D may be a value which is obtained by dividing 10240 by y(i.e., int(10240/y)), whereby they second-type-exclude-subframes areevenly distributed over a total of 10240 subframes.

In this instance, when a second-type-exclude-subframe determined asdescribed above overlaps a first-type-exclude-subframe (that is, whenthe second-type-exclude-subframe has the same subframe index as that ofthe first-type-exclude-subframe) or when the determinedsecond-type-exclude subframe is not an uplink subframe, only withrespect to the second-type-exclude-subframe that overlaps thefirst-type-exclude-subframe (the subframe in which SLSS transmission isperformed) or the second-type-exclude subframe that is not an uplinksubframe, a subframe, which is not the first-type-exclude-subframe, butis an uplink subframe and is the closest subframe from among subframessubsequent to the subframe determined as described above, may bedetermined to be a second-type-exclude-subframe.

In other words, subframes corresponding to subframe indices y_(n) in asingle SFN (or DFN) period may be second-type-exclude-subframes. Here,it is defined that y_(n)=d+D*n and n=0, 1,. . . , y-1. One of theinteger values that satisfies 0≦d<D may be selected as d. For example, dmay be an uplink subframe which is the closest to a subframe having asubframe index value of D, from among subframes prior to the subframehaving the subframe index value of D. However, the value is not limitedthereto. Similarly, D may be int(10240/y), but it is not limitedthereto. When a second-type-exclude-subframe defined by the equationy_(n)=d+D*n overlaps a first-type-exclude subframe (i.e., a subframe inwhich SLSS transmission is performed) or is not an uplink subframe, asubframe, which is different from a first-type-exclude subframe, is anuplink subframe, and is the closest subframe from among subframessubsequent to the second-type-exclude-subframe defined by the equationy_(n)=d+D*n may be defined as a second-type-exclude-subframe.

FIG. 12 is a flowchart illustrating a method of determining a resourcepool.

In the example of FIG. 12, a first UE and a second UE correspond to UEsthat join in V2X communication or direct link communication, wherein thefirst UE corresponds to an SA and data Tx UE, and the second UEcorresponds to an SA and data Rx UE.

In operation S210, an eNodeB may transmit resource pool configurationinformation for V2X communication, SLSS configuration information, andthe like to the first UE. If the eNodeB transmits the informationthrough higher layer signaling, the resource pool configurationinformation may correspond to “subframe indication of resource pool”information including a bitmap having a length of L_(bitmap). Also, theSLSS configuration information may correspond to “SL V2V synchronizationconfiguration” information (i.e., configuration information associatedwith whether a UE transmits and receives synchronization informationassociated with a sidelink for V2V).

In operation S1220, the first UE may determine xfirst-type-exclude-subframes (i.e., subframes in which an SLSS resourceis configured) based on the SLSS configuration information. Accordingly,the x first-type-exclude-subframes may be excluded from a set of allsubframes belonging to a predetermined period (e.g., 10240 subframeswhich correspond to all subframes in a single SFN (or DFN) period).Here, the set of subframes remaining after excluding the xfirst-type-exclude-subframe from the set of all subframes may bereferred to as a first subset. For example, x=0 or 64.

In operation S1230, the first UE may repeatedly apply a bitmap havingthe length of L_(bitmap) received in operation S1210 to the set ofsubframes (i.e., a first subset) remaining after excluding the xfirst-type-exclude-subframes from the set of all subframes determined inoperation S1220. That is, unlike the example shown in FIG. 11 whichtakes into consideration a second-type-exclude-subframe, the exampleshown in FIG. 12 does not take into consideration asecond-type-exclude-subframe (e.g., it does not define asecond-type-exclude-subframe or assumes that the number ofsecond-type-exclude-subframes is 0 (y=0)), and applies a bitmap afterexcluding a first-type-exclude-subframe.

Operation S1235 may be performed when the first UE is set to operate inthe eNodeB resource scheduling mode (mode 3), and may be omitted whenthe first UE is set to operate in the UE autonomous resource selectionmode (mode 4). In operation S1235, the eNobeB may transmit DCI to thefirst UE, including scheduling information (or grant information) of SAand/or data transmission.

In operation S1240, when the first UE is set to operate in the eNodeBresource scheduling mode (mode 3), the first UE may determine a resource(e.g., a subframe and a sub-channel) to be used for transmitting SAand/or data to the second UE based on the DCI received from the eNodeB.When the first UE is set to operate in the UE autonomous resourceselection mode (mode 4), the UE may autonomously determine a resource tobe used for transmitting SA and/or data to the second UE. As an example,the first UE may determine a resource through which SA and/or data is tobe transmitted by taking into consideration the state of channeloccupancy by a sensing window in a predetermined interval prior to thepoint in time when a TB to be transmitted to the second UE has beengenerated.

In operation S1250, the first UE determines a resource reservationinterval (P_(rsvp)) and a resource reservation multiple parameter (j),and may determine transmission reservation subframes based thereon.

A fixed value (e.g., P_(rsvp)=100) may always be used as P_(rsvp) inoperation S1250, or one selected from among a plurality of values may beused as P_(rsvp).

When one fixed value is always used as P_(rsvp), P_(rsvp) may always be100 irrespective of the value of L_(bitmap) (16, 20, or 100).

When a value selected from among the plurality of values is used asP_(rsvp), P_(rsvp) may be directly indicated by higher layer signaling.P_(rsvp) may be determined in connection with L_(bitmap). Further,P_(rsvp) may be determined based on L_(bitmap) and on informationassociated with whether a short resource reservation period is used.

When one value selected from among a plurality of values is used asP_(rsvp) and when P_(rsvp) is indicated directly by higher layersignaling, either 25 (if the reservation period is short) or 100 may beselected as P_(rsvp), irrespective of the value of L_(bitmap) (16, 20,or 100).

When one value selected from among a plurality of values is used asP_(rsvp) and when P_(rsvp) is determined in connection with L_(bitmap),an eNodeB may directly transmit the value of P_(rsvp) determined inconnection with L_(bitmap) (or a value indicating a combination ofP_(rsvp) and L_(bitmap)) to the first UE. Further, the first UE mayautonomously determine the value of P_(rsvp) associated with the valueof L_(bitmap) based on the value of L_(bitmap) received from the eNodeBin operation S1210. The value of P_(rsvp) associated with the value ofL_(bitmap) may be determined as shown in Table 11 below. In thisinstance, when the value of P_(rsvp) is a multiple of 16, the value maybe 16, 32, 96, or 112, wherein 16 and 32 are multiples of 16 that areclose to 25 (if the reservation period is short), and 96 and 112 aremultiples of 16 that are close to 100. However, the value is not limitedthereto.

TABLE 11 L_(bitmap) P_(rsvp) 100 100 20 100 16 One of valuescorresponding to multiples of 16

When one value selected from among a plurality of values is used asP_(rsvp), and when P_(rsvp) is determined based on L_(bitmap) and oninformation associated with whether a short resource reservation periodis used, the eNodeB may directly transmit the value of P_(rsvp), whichis determined based on L_(bitmap) and on information associated withwhether a short resource reservation period is used, to the first UE. Asa second option, the eNodeB may directly transmit a value indicating thecombination of the information associated with whether a short resourcereservation period is used and L_(bitmap). Further, the first UE mayautonomously determine the value of P_(rsvp) in association with theinformation associated with whether a short resource reservation periodis used and L_(bitmap) based on the information associated with whethera short resource reservation period is used (information whether a shortreservation period is used or not may be indicated by the eNodeB throughhigher layer signaling such as RRC or the like) and L_(bitmap) receivedfrom the eNodeB in operation S1110.

To provide one example, the value of P_(rsvp) in association with thevalue of L_(bitmap) and with whether a short reservation period is usedmay be determined as shown in Table 12. In this instance, when the valueof P_(rsvp) is one of the values corresponding to multiples of 16 inTable 12, the value may be either 16 or 32, which are multiples of 16that are close to 25, when a short reservation period is used, or thevalue may be either 96 or 112, which are multiples of 16 that are closeto 100, when a short reservation period is not used. However, the valueis not limited thereto.

TABLE 12 Short reservation period L_(bitmap) P_(rsvp) Not used 100 100Not used 20 100 Not used 16 One of values corresponding to multiples of16 Used 100  25 Used 20  25 Used 16 One of values corresponding tomultiples of 16

As described above, even when L_(bitmap)=16, 100 may be used as thevalue of P_(rsvp). However, in the case of L_(bitmap)=16, when a bitmaphaving a length of 16 bits is (b₀, b₁, b₂, . . . , b₁₅), P_(rsvp)=100.Accordingly, subframes in units of multiples of 100 may or may notbelong to a single subframe pool. The bit values of (b₀, b₄, b₈, b₁₂)need to always be the same. In the same manner, the bit values of (b₁,b₅, b₉, b₁₃) needs to always be the same. The bit values of (b₂, b₆,b₁₀, b₁₄) need to always be the same. The bit values of (b₃, b₇, b₁₁,b₁₅) need to always be the same. This is merely a four-bit bitmaprepeated four times, as opposed to a 16-bit bitmap. Therefore, theconfiguration of a bitmap may have restrictions.

Even there are restrictions, in order to set the resource reservationinterval P_(rsvp) to be P_(rsvp) the same in all cases, the value ofP_(rsvp), which is the same as the value of (P_(rsvp)=100) whenL_(bitmap)=20 or 100, may be used when L_(bitmap)=16.

Alternatively, to overcome restrictions: when 100 subframes correspondto P_(rsvp)=100, a bitmap (b₀, b₁, b₂, b₁₅) having a length of 16 in thecase of L_(bitmap)=16, is applied six times and only a part (b₀, b₁, b₂,b₃) is applied with respect to the last four subframes. With respect tosubsequent sets of 100 subframes, the bitmap (b₀, b₁, b₂, . . . , b₁₅)having a length of 16 is applied six times and only front four bits (b₀,b₁, b₂, b₃) of the bitmap are applied with respect to the last foursubframes, in the same manner as described above. In this manner, whenthe bitmap having a length of 16 is applied with respect to 10240subframes included in a single SFN (or DFN) period for every 100subframes, as described above, the above restriction may not exist.However, it is the same as the case in which a bit value is appliedbased on a 100-subframe period. Therefore, ambiguity attributable to SFN(or DFN) wrap-around may occur, as in the case of L_(bitmap)=20 or 100.

Therefore, in the case of L_(bitmap)=16, one of the multiples of 16 maybe set as P_(rsvp) as described above to overcome the above restriction.In this instance, the restriction caused when P_(rsvp) is indivisible byL_(bitmap) may be overcome, and at the same time, ambiguity attributableto SFN (or DFN) wrap-around may not be generated because the the totalnumber of subframes in a single SFN (or DFN) period (10240) is divisibleby the value of L_(bitmap) (16). However, in this instance, the resourcereservation interval P_(rsvp) must be set to be different from the caseof L_(bitmap)=20 or 100. Therefore, the number of events, which areneeded to be taken into consideration in a resource reservation process,may be increased.

Also, the first UE may determine a resource reservation multipleparameter j based on the length L_(bitmap) of a bitmap and/or on thenumber of first-type-exclude-subframes (x). Here, whether a resourcewill be reserved beyond a single predetermined period (e.g., a SFNperiod or a DFN period) may be determined based on j (=1, 2, . . . ,C_(resel)-1). That is, whether an SFN (or DFN) wrap-around situationwill occur may be determined. The maximum value (upper limit) of jassociated with the value of L_(bitmap) may be determined as shown inTable 13 or Table 14.

TABLE 13 L_(bitmap) x C_(resel) 100 0 6*SL_RESOURCE_RESELECTION_COUNTER100 64 6*SL_RESOURCE_RESELECTION_COUNTER 20 010*SL_RESOURCE_RESELECTION_COUNTER 20 646*SL_RESOURCE_RESELECTION_COUNTER 16 010*SL_RESOURCE_RESELECTION_COUNTER 16 6410*SL_RESOURCE_RESELECTION_COUNTER

TABLE 14 L_(bitmap) C_(resel) 100 6*SL_RESOURCE_RESELECTION_COUNTER 206*SL_RESOURCE_RESELECTION_COUNTER 16 10*SL_RESOURCE_RESELECTION_COUNTER

In the examples described in Table 13 and Table 14, when the value ofL_(bitmap) is 100, the upper limit of j may be lowered to j=1, 2, . . ., 6*SL_RESOURCE_RESELECTION_COUNTER-1 because an SFN (or DFN)wrap-around situation needs to be avoided irrespective of x.

In the example described in Table 13, when the value of L_(bitmap) is 20and when x=64, the upper limit of j may be lowered to j=1, 2, . . . ,6*SL_RESOURCE_RESELECTION_COUNTER-1 because an SFN (or DFN) wrap-aroundsituation needs to be avoided.

In the example described in Table 13, when the value of L_(bitmap) is 20and x=0, ambiguity does not exist even though an SFN (or DFN)wrap-around situation does occur, and the sequence j=1, 2, . . . ,10*SL_RESOURCE_RESELECTION_COUNTER-1 may be applied.

Alternatively, as shown in Table 14, when the value of L_(bitmap) is 20,it is assumed that an SFN (or DFN) wrap-around situation does not occurirrespective of x. In this instance, the sequence j=1, 2, . . . ,6*SL_RESOURCE_RESELECTION_COUNTER-1 may be applied.

In the examples of Table 13 and Table 14, when the value of L_(bitmap)is 16, ambiguity does not exist even though an SFN (or DFN) wrap-aroundsituation does occur, whereby j=1, 2, . . . ,10*SL_RESOURCE_RESELECTION_COUNTER-1 may be applied.

In operations S1260 and S1270, the first UE may map SA and data to theresource determined in operation S1240, and may transmit the same to thesecond UE. For example, in operation S1260, the first UE may transmit SAcorresponding to SCI to the second UE. In operation S1270, the first UEmay transmit data to the second UE in a resource indicated by the SCItransmitted in operation S1260.

In operation S1280, the second UE may attempt to receive the SA from thefirst UE according to a blind decoding scheme. The blind decoding schememay include monitoring the locations of candidate resources throughwhich SA may be received. In addition, the second UE may determine theresource in which data is to be received based on the SCI received fromthe first UE, and may attempt to decode the data transmitted from thefirst UE.

Although the above described illustrative methods of FIG. 12 areexpressed as a series of operations, the order of operations executed isnot limited to those described. The operations may additionally beexecuted in parallel or in a different order. In order to implement thesystem described above, other operations may be added to the describedoperations, only some operations may be performed while excludingothers, or some operations may be excluded while additional otheroperations may be included.

Next, more detailed examples associated with FIG. 12 will be described.

According to a feature of the example shown in FIG. 12, the selection ofa combination of L_(bitmap) and P_(rsvp) may be restricted, and theupper limit of a resource reservation multiple parameter j may be set,by taking into consideration whether an SFN (or DFN) wrap-around occurs.

Embodiment 5

The present embodiment relates to the case in which L_(bitmap)=16 andx=0. In this instance, a subframe pool is determined to be t^(SL) _(k)(here,0≦k<(10240-0)). That is, a first-type-exclude-subframe and asecond-type-exclude-subframe may not exist, and a bitmap may berepeatedly applied to all subframes in a predetermined period. In thisinstance, a bitmap having a length of 16 is repeatedly applied to 10240subframes, and thus, the number of target subframes to which the bitmapis to be applied (i.e., Tmax) may be an integer multiple of the lengthof the bitmap (i.e., the number of target subframes to which the bitmapis to be applied is divisible by the length of the bitmap).

In addition, the value of P_(rsvp) may be set to an appropriate valuefor controlling a resource reservation period. As described above, afixed value (e.g., P_(rsvp)=100) may always be used as P_(rsvp) or oneselected from among a plurality of values may be used as P_(rsvp). Whena value selected from among the plurality of values is used, P_(rsvp)may be directly indicated by higher layer signaling. Otherwise, P_(rsvp)may be determined in connection with L_(bitmap), or P_(rsvp) may bedetermined based on L_(bitmap) and on information associated withwhether a short resource reservation period is used.

Embodiment 6

The present embodiment relates to the case in which L_(bitmap)=16 andx=64. In this instance, a subframe pool is determined to be t^(SL) _(k)(here,0≦k<(10240-64)). That is, a bitmap may be repeatedly applied to afirst subset that takes into consideration 64first-type-exclude-subframes (x=64) (here, asecond-type-exclude-subframe does not exist). In this example, a bitmaphaving a length of 16 is repeatedly applied to 10176 subframes, andthus, the number of target subframes to which the bitmap is to beapplied (i.e., Tmax) may be an integer multiple of the length of thebitmap (i.e., the number of target subframes to which the bitmap is tobe applied is divisible by the length of the bitmap).

Here too, the value of P_(rsvp) may be set to an appropriate value forcontrolling a resource reservation period. As described above, a fixedvalue (e.g., P_(rsvp)=100) may always be used as P_(rsvp) or oneselected from among a plurality of values may be used as P_(rsvp). Whena value selected from among the plurality of values is used, P_(rsvp)may be directly indicated by higher layer signaling. Otherwise, P_(rsvp)may be determined in connection with L_(bitmap), or P_(rsvp) may bedetermined based on L_(bitmap) and on information associated withwhether a short resource reservation period is used.

The various embodiments of the present disclosure are not described heremerely for enumerating all possible combinations. Rather, they describerepresentative aspects of the present disclosure, and subjects describedin the various embodiments may be applied independently or incombination of two or more subjects.

In addition, the various embodiments of the present disclosure may beimplemented by hardware, firmware, software, a combination thereof, orthe like. In the case of hardware, the various embodiments of thepresent disclosure may be implemented by one or more of ApplicationSpecific Integrated Circuits (ASICs), Digital Signal Processors (DSPs),Digital Signal Processing Devices (DSPDs), Programmable Logic Devices(PLDs), Field Programmable Gate Arrays (FPGAs), a general processor, acontroller, a micro-controller, a micro-processor, and the like.

The scope of the present disclosure includes software ormachine-executable instructions (e.g., an operating system, anapplication, firmware, a program, and the like) which enable operationsaccording to the methods of various embodiments to be performed in adevice or a computer. The scope also includes a device that stores suchsoftware, instructions, or the like, or a non-transitorycomputer-readable medium which is executable on a computer.

FIG. 13 is a diagram illustrating the configuration of a wirelessdevice.

FIG. 13 illustrates a UE 100 that transmits control information and datafor V2X communication or direct link (e.g., D2D, ProSe, or SL)communication to another UE, and an eNodeB 200 that provides controlinformation to the UE 100 for the purpose of supporting V2Xcommunication or direct link (e.g., D2D, ProSe, or SL) communication.

The UE 100 may include a processor 110, an antenna unit 120, atransceiver 130, and memory 140.

The processor 110 processes signals related to a baseband, and mayinclude a higher layer processing unit 111 and a physical layerprocessing unit 112. The higher layer processing unit 111 may processthe operations of a Medium Access Control (MAC) layer, a Radio ResourceControl (RRC) layer, or a higher layer. The physical layer processingunit 112 may process the operations of a PHY layer (e.g., processing anuplink transmission signal or processing a downlink reception signal).The processor 110 may control operation of the UE 100 in addition toprocessing signals related to a baseband.

The antenna unit 120 may include one or more physical antennas, and maysupport Multiple Input Multiple Output (MIMO) transmission/receptionwhen a plurality of antennas is included. The transceiver 130 mayinclude a Radio Frequency (RF) transmitter and an RF receiver. Thememory 140 may store information processed by the processor 110 as wellas software, an operating system (OS), applications, or the likeassociated with the operations of the UE 100; the memory mayadditionally include elements such as a buffer or the like.

The eNodeB 200 may include a processor 210, an antenna unit 220, atransceiver 230, and a memory 240.

The processor 210 processes signals related to a baseband, and mayinclude a higher layer processing unit 211 and a physical layerprocessing unit 212. The higher layer processing unit 211 may processthe operations of an MAC layer, an RRC layer, or a higher layer. Thephysical layer processing unit 212 may process the operations of a PHYlayer (e.g., processing a downlink transmission signal or processing anuplink reception signal). The processor 210 may control operation of theeNodeB 200 in addition to processing signals related to a baseband.

The antenna unit 220 may include one or more physical antennas, and maysupport MIMO transmission/reception when a plurality of antennas isincluded. The transceiver 230 may include an RF transmitter and an RFreceiver. The memory 240 may store information processed by theprocessor 210 as well as software, an OS, applications, or the likeassociated with the operations of the eNodeB 200; the memory mayadditionally include elements such as a buffer or the like.

The processor 110 of the UE 100 may be configured to implement theoperations of a UE, which have been described in all of the embodimentsof the present disclosure.

For example, the higher layer processing unit 111 of the processor 110of the UE 100 may include a first/second-type-exclude-subframedetermining unit 1310, a resource pool determining unit 1230, and atransmission reservation subframe determining unit 1330.

The first/second-type-exclude-subframe determining unit 1310 maydetermine a first-type-exclude-subframe based on predetermined subframeconfiguration information (e.g., SLSS configuration information)received from an eNodeB. The first/second-type-exclude-subframedetermining unit 1310 may also determine whether asecond-type-exclude-subframe is needed, and may determine the number ofsecond-type-exclude-subframes and the locations thereof (or a patternthereof) when a second-type-exclude-subframe is needed.

The resource pool determining unit 1320 may determine a subframe pool byrepeatedly applying bitmap information to the subframes (e.g., a secondsub-set) remaining after excluding first/second-type-exclude-subframesfrom all subframes included in a predetermined period (e.g., a SFNperiod or DFN period). The predetermined period is based on resourcepool configuration information (e.g., bitmap information) received froman eNodeB.

When SA and/or data to be transmitted to another UE exists, one UE 100may transmit that SA and/or data to another UE in one or more subframesof the subframe pool through the physical layer processing unit 112.

A transmission reservation subframe determining unit 1330 may determinea subframe having an index value of m+P_(rsvp)*j, based on index m of asubframe where SA and/or data transmission is performed.

Herein, as described in the various embodiments of the presentdisclosure, the number of second-type-exclude-subframes, the pattern ofsecond-type-exclude-subframes, a resource reservation multiple parameter(j), and the like may be determined by taking into consideration thelength of a bitmap, the number of first-type-exclude-subframes, aresource reservation interval (P_(rsvp)), and the like.

The physical layer processing unit 112 of the processor 110 of the UE100 may receive information from the eNodeB 200, such as DCI or thelike, and may deliver the same to the higher layer processing unit 111,or may transmit control information and data to another UE (notillustrated).

The processor 210 of the eNodeB 200 may be configured to implementoperations of the eNodeB which have been described in the embodiments ofthe present disclosure.

For example, the higher layer processing unit 211 of the processor 210in the eNodeB 200 may include a resource pool configuration informationgenerating unit 1350, a predetermined-subframe configuration informationgenerating unit 1360, and a resource reservation interval and resourcereservation multiple parameter configuration information generating unit1370.

The resource pool configuration information generating unit 1350 maygenerate information including bitmap information and the like.

The predetermined-subframe configuration information generating unit1360 may generate information associated with an SLSS configurationsubframe, which the UE 100 regards as a first-type-exclude-subframe.

The resource reservation interval and resource reservation multipleparameter configuration information generating unit 1370 may generateinformation required for setting a resource reservation interval(P_(rsvp)), a resource reservation multiple parameter (j), and the like,which are required when the UE 100 determines a transmission reservationsubframe m+P_(rsvp)*j.

As described above, the information generated by the higher layerprocessing unit 211 may be transferred in the form of higher layersignaling to the UE 100 through the physical layer processing unit 212.

A mobile device, e.g., a V2X UE, may perform a process of determining aresource pool for a sidelink transmission. For example, the mobiledevice may receive, from an eNB, resource pool configurationinformation, the resource pool configuration information comprising abitmap to determine the resource pool, determine, for a period having aplurality of consecutive subframes, a first subset of subframes byexcluding, from the plurality of consecutive subframes, subframes inwhich a sidelink synchronization signal (SLSS) resource is configured;and subframes other than uplink subframes. The mobile device maydetermine, for the period, a second subset of subframes by excluding,from the first subset of subframes, one or more subframes, wherein aquantity of the second subset of subframes corresponds to an integermultiple of a length of the bitmap, and determine, based on a pluralityof repetitions of the bitmap, the resource pool for a sidelinktransmission from the second subset of subframes.

The mobile device may receive, from the eNB, a downlink controlinformation (DCI) indicating the sidelink transmission, determine, basedon the DCI, a data transmission subframe, among the resource pool, fortransmitting sidelink data, and transmit, to another mobile device andin the determined data transmission subframe, the sidelink data.

The mobile device may receive, from the eNB, information of a resourcereservation interval, determine, based on the determined datatransmission subframe and the resource reservation interval, one or moretransmission reservation subframes, and reserve a transmission of thesidelink data in the one or more transmission reservation subframes.

In TDD cell, the subframes other than uplink subframes may be TimeDivision Duplex (TDD) downlink subframes and TDD special subframes. Themobile device may receive, from the eNB, SLSS configuration informationindicating the SLSS resource.

The mobile device may determine the period based on a system framenumber (SFN) reset period or a direct frame number (DFN) reset period.For example, the period may be 10240 subframes because the SFN and DFNeach has indexes from 0 to 1023, and each system frame or direct framehas ten subframes.

The mobile device may include one or more of: a vehicle-to-everything(V2X) device or a vehicle-to-vehicle (V2V) device. The resource pool fora sidelink transmission may correspond to one or more of: a resourcepool for a V2X sidelink communication or a resource pool for a V2Vsidelink communication.

The determining the second subset of subframes may include determining aquantity of the first subset of subframes, performing a modulo operationbased on the quantity of the first subset of subframes and a quantity ofbits in the bitmap, and determining the one or more subframes based onthe modulo operation.

Further, a mobile device may perform a process of determining a resourcepool for a sidelink transmission by: receiving, from an evolved NodeB(eNB), resource pool configuration information, the resource poolconfiguration information comprising a bitmap to determine the resourcepool; determining, for a period having a plurality of Frequency DivisionDuplex (FDD) subframes, a first subset of subframes by excluding, fromthe plurality of FDD subframes, subframes in which a sidelinksynchronization signal (SLSS) resource is configured; determining, forthe period, a second subset of subframes by excluding, from the firstsubset of subframes, one or more subframes, wherein a quantity of thesecond subset of subframes corresponds to an integer multiple of alength of the bitmap; and determining, based on a plurality ofrepetitions of the bitmap, the resource pool for a sidelink transmissionfrom the second subset of subframes.

Further, a mobile device may perform a process of determining a resourcepool for a sidelink transmission by: receiving, from an evolved NodeB(eNB), resource pool configuration information, the resource poolconfiguration information comprising a bitmap to determine the resourcepool; determining, for a period having a plurality of consecutivesubframes, a first subset of subframes by excluding, from the pluralityof consecutive subframes: subframes in which a sidelink synchronizationsignal (SLSS) resource is configured; and subframes other than uplinksubframes; performing a modulo operation based on a quantity of thefirst subset of subframes and a length of the bitmap to determine one ormore subframes to be excluded from the first subset of subframes;determining, for the period, a second subset of subframes by excluding,from the first subset of subframes, the one or more subframes, wherein aquantity of the second subset of subframes corresponds to an integermultiple of the length of the bitmap; and determining, based on aplurality of repetitions of the bitmap, the resource pool for a sidelinktransmission from the second subset of subframes.

The above description is to explain the technical aspects of exemplaryembodiments of the present invention, and it will be apparent to thoseskills in the art that modifications and variations can be made withoutdeparting from the spirit and scope of the present invention. Thus, itis intended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of determining a resource pool for asidelink transmission, the method comprising: receiving, at a mobiledevice and from an evolved NodeB (eNB), resource pool configurationinformation, the resource pool configuration information comprising abitmap to determine the resource pool; determining, for a period havinga plurality of consecutive subframes, a first subset of subframes byexcluding, from the plurality of consecutive subframes: subframes inwhich a sidelink synchronization signal (SLSS) resource is configured;and subframes other than uplink subframes; determining, for the period,a second subset of subframes by excluding, from the first subset ofsubframes, one or more subframes, wherein a quantity of the secondsubset of subframes corresponds to an integer multiple of a length ofthe bitmap; and determining, based on a plurality of repetitions of thebitmap, the resource pool for a sidelink transmission from the secondsubset of subframes.
 2. The method of claim 1, further comprising:receiving, at the mobile device and from the eNB, a downlink controlinformation (DCI) indicating the sidelink transmission; determining,based on the DCI, a data transmission subframe, among the resource pool,for transmitting sidelink data; and transmitting, to another mobiledevice and in the determined data transmission subframe, the sidelinkdata.
 3. The method of claim 2, further comprising: receiving, from theeNB, information of a resource reservation interval; determining, basedon the determined data transmission subframe and the resourcereservation interval, one or more transmission reservation subframes;and reserving a transmission of the sidelink data in the one or moretransmission reservation subframes.
 4. The method of claim 1, whereinthe subframes other than uplink subframes are Time Division Duplex (TDD)downlink subframes and TDD special subframes.
 5. The method of claim 1,further comprising receiving, at the mobile device and from the eNB,SLSS configuration information indicating the SLSS resource.
 6. Themethod of claim 1, further comprising determining the period based on asystem frame number (SFN) reset period or a direct frame number (DFN)reset period.
 7. The method of claim 1, wherein the mobile devicecomprises one or more of: a vehicle-to-everything (V2X) device or avehicle-to-vehicle (V2V) device, and wherein the resource pool for asidelink transmission corresponds to one or more of: a resource pool fora V2X sidelink communication or a resource pool for a V2V sidelinkcommunication.
 8. The method of claim 1, wherein the determining thesecond subset of subframes comprises: determining a quantity of thefirst subset of subframes; performing a modulo operation based on thequantity of the first subset of subframes and a quantity of bits in thebitmap; and determining the one or more subframes based on the modulooperation.
 9. A method of determining a resource pool for a sidelinktransmission, the method comprising: receiving, at a mobile device andfrom an evolved NodeB (eNB), resource pool configuration information,the resource pool configuration information comprising a bitmap todetermine the resource pool; determining, for a period having aplurality of Frequency Division Duplex (FDD) subframes, a first subsetof subframes by excluding, from the plurality of FDD subframes,subframes in which a sidelink synchronization signal (SLSS) resource isconfigured; determining, for the period, a second subset of subframes byexcluding, from the first subset of subframes, one or more subframes,wherein a quantity of the second subset of subframes corresponds to aninteger multiple of a length of the bitmap; and determining, based on aplurality of repetitions of the bitmap, the resource pool for a sidelinktransmission from the second subset of subframes.
 10. The method ofclaim 9, further comprising: receiving, at the mobile device and fromthe eNB, a downlink control information (DCI) indicating the sidelinktransmission; determining, based on the DCI, a data transmissionsubframe, among the resource pool, for transmitting sidelink data; andtransmitting, to another mobile device and in the determined datatransmission subframe, the sidelink data.
 11. The method of claim 10,further comprising: receiving, from the eNB, information of a resourcereservation interval; determining, based on the determined datatransmission subframe and the resource reservation interval, one or moretransmission reservation subframes; and reserving a transmission of thesidelink data in the one or more transmission reservation subframes. 12.The method of claim 9, further comprising receiving, at the mobiledevice and from the eNB, SLSS configuration information indicating theSLSS resource.
 13. The method of claim 9, further comprising determiningthe period based on a system frame number (SFN) reset period or a directframe number (DFN) reset period.
 14. The method of claim 9, wherein themobile device comprises one or more of: a vehicle-to-everything (V2X)device or a vehicle-to-vehicle (V2V) device, and wherein the resourcepool for a sidelink transmission corresponds to one or more of: aresource pool for a V2X sidelink communication or a resource pool for aV2V sidelink communication.
 15. The method of claim 9, wherein thedetermining the second subset of subframes comprises: determining aquantity of the first subset of subframes; performing a modulo operationbased on the quantity of the first subset of subframes and a quantity ofbits in the bitmap; and determining the one or more subframes based onthe modulo operation.
 16. A method of determining a resource pool for asidelink transmission, the method comprising: receiving, at a mobiledevice and from an evolved NodeB (eNB), resource pool configurationinformation, the resource pool configuration information comprising abitmap to determine the resource pool; determining, for a period havinga plurality of consecutive subframes, a first subset of subframes byexcluding, from the plurality of consecutive subframes: subframes inwhich a sidelink synchronization signal (SLSS) resource is configured;and subframes other than uplink subframes; performing a modulo operationbased on a quantity of the first subset of subframes and a length of thebitmap to determine one or more subframes to be excluded from the firstsubset of subframes; determining, for the period, a second subset ofsubframes by excluding, from the first subset of subframes, the one ormore subframes, wherein a quantity of the second subset of subframescorresponds to an integer multiple of the length of the bitmap; anddetermining, based on a plurality of repetitions of the bitmap, theresource pool for a sidelink transmission from the second subset ofsubframes.
 17. The method of claim 16, wherein the subframes other thanuplink subframes are Time Division Duplex (TDD) downlink subframes andTDD special subframes.
 18. The method of claim 16, further comprisingreceiving, at the mobile device and from the eNB, SLSS configurationinformation indicating the SLSS resource.
 19. The method of claim 16,further comprising determining the period based on a system frame number(SFN) reset period or a direct frame number (DFN) reset period.
 20. Themethod of claim 16, wherein the mobile device comprises one or more of:a vehicle-to-everything (V2X) device or a vehicle-to-vehicle (V2V)device, and wherein the resource pool for a sidelink transmissioncorresponds to one or more of: a resource pool for a V2X sidelinkcommunication or a resource pool for a V2V sidelink communication.